RIDEX Zündkerze VW,AUDI,MERCEDES-BENZ 686S0028 9807B561BW,MN1632364,32017042 Zündkerzen,Kerzen,Zuendkerzen 32017044,101654016,9807B5617W,9807B561CW

Elektrodenabstand [mm]: 0,7; Anzugsdrehmoment [Nm]: 28; Anziehwinkel [Grad]: 90; Außengewinde [mm]: 14; Gewindesteigung [mm]: 1,25; Gewindelänge [mm]: 19; Schlüsselweite: 16; Funkenlage [mm]: 4; Anzahl der Steckkontakte: 1; Anschlusstechnik: SAE/M4; Zündkerze: 1-Masseelektrode, Iridium-Mittelelektrode; Zündkerze: zwei gleiche Zündkerzen pro Zylinder; Kraftstoffart: CNG/LPG; Ersetzen nach km: 30000; Baujahr bis: 12/1996, 12/1998, 12/1995, 11/2015, 09/1994, 07/1988, 05/1995, 03/1997, 12/1997, 10/1997, 02/1998, 12/2005, 06/1998, 09/1995, 06/1994, 05/1999, 04/1997, 06/1990, 04/1992, 10/1995, 12/1994, 08/1989, 03/2001, 08/1994, 01/1996, 01/1999, 03/1996, 02/1996, 08/2014, 12/2001, 11/1995, 05/1992, 05/1996, 03/2009, 03/1991, 07/1994, 05/1994, 08/1993, 03/1994, 02/2002, 02/2001, 05/2000, 08/1999, 06/1996, 07/2001, 02/1999, 04/1998, 07/1995, 11/1997, 11/1996, 07/1998, 01/1997, 12/2015, 10/1999, 12/1993, 07/1996, 06/1997, 11/1998, 05/1997, 05/2010, 07/1999, 10/1996, 06/2000, 10/2000, 02/2000, 04/1996, 08/1996, 08/1998, 02/2005, 09/2000, 11/2000, 06/1999, 08/2001, 10/2001, 04/2000, 10/1998, 09/2001, 09/1998, 03/1999, 10/2002, 12/2016, 08/2011, 04/2004, 04/1999, 12/1999, 11/2002, 04/2008, 01/2000, 08/1997, 08/1995, 08/1992, 07/2000, 03/2000, 03/1998, 05/2004, 12/2000, 06/2004, 05/2007, 05/2001, 08/2002, 04/2001, 09/1999, 04/2002, 03/2002, 07/2002, 08/2000, 01/2003, 12/2003, 06/2001, 12/2014, 05/2003, 11/2001, 06/2007, 12/2007, 06/2003, 10/2007, 11/1993, 05/2013, 06/2014, 07/2005, 10/2005, 02/2009, 09/2004, 12/2010, 05/2002, 09/2003, 09/2002, 06/2009, 04/2012, 10/2008, 08/2015, 12/2002, 06/2010, 08/2012, 09/2010, 12/2011, 07/2004, 05/2005, 04/2003, 09/2005, 04/2010, 02/1995, 12/2008, 08/2010, 09/2013, 09/2014, 04/2009, 01/2005, 04/2007, 03/2006, 07/2003, 03/2004, 10/2004, 08/2003, 09/2006, 07/2007, 06/2002, 08/2006, 01/2004, 07/2009, 05/2006, 09/2007, 12/2006, 12/2004, 08/2005, 03/2005, 01/2002, 09/2009, 10/2012, 07/2006, 11/2005, 07/2008, 08/2009, 02/2006, 06/2006, 11/2006, 12/2012, 12/2009, 10/2006, 08/2007, 10/2009, 05/2009, 11/2010, 08/2004, 11/2004, 02/2011, 10/2010, 04/2013, 08/2008, 06/2008, 05/2012, 02/2010, 02/2007, 03/2010, 01/2008, 11/1994, 10/2011, 11/2008, 07/1997, 12/2013, 09/1996, 04/2005, 01/2011, 03/2008, 09/1997, 09/2012, 03/2012, 11/2012, 01/2010, 08/2016, 05/2018, 06/2012, 06/2013, 05/2011, 03/2007, 06/2015, 07/2012; TECDOC-Motornummer: 28375, 28376, 17422, 1154, 305, 224, 3213, 3211, 5080, 735, 736, 6554, 2863, 2864, 4841, 2777, 5396, 14729, 994, 1070, 893, 4387, 3518, 3480, 26410, 28372, 2852, 2866, 3212, 4447, 4982, 4988, 9991, 2354, 5101, 1949, 1951, 2016, 1722, 4525, 4516, 4511, 1565, 4326, 5441, 20017, 20780, 4199, 13929, 13950, 4979, 14913, 13391, 13828, 28380, 1076, 4512, 4513, 2999, 2853, 26242, 9450, 9451, 12848, 15611, 241, 13775, 13776, 16412, 15335, 13949, 25586, 17999, 1839, 4197, 13931, 13932, 13930, 9516, 19270, 661, 14731, 5074, 9990, 11588, 5075, 3453, 3454, 9386, 14908, 12488, 5536, 5353, 9893, 5557, 11497, 16237, 5558, 5560, 15808, 16259, 16260, 5143, 9366, 35155, 1966, 6816, 6817, 14748, 5499, 2521, 5520, 5521, 16274, 16275, 4876, 5534, 3850, 15288, 15370, 8507, 17848, 3183, 3820, 9515, 13951, 13952, 13953, 4667, 9404, 17995, 3184, 18004, 18527, 25572, 16737, 9363, 9456, 15486, 16385, 9518, 14029, 15329, 3634, 20534, 10887, 14914, 28385, 10813, 4396, 18211, 13442, 10607, 11927, 18049, 14328, 14329, 17266, 17267, 9623, 17271, 17470, 17899, 14909, 9624, 17272, 17851, 9848, 14728, 32501, 3798, 11347, 15352, 15353, 16331, 15479, 12509, 12510, 15488, 15489, 15490, 9453, 9454, 13468, 15474, 17930, 16189, 26299, 11357, 15342, 15343, 25167, 16269, 11088, 14028, 15330, 15336, 15355, 26300, 11591, 11358, 13308, 13309, 16346, 16345, 13310, 16349, 9476, 30122, 26867, 19728, 23410, 29542, 13729, 18178, 13869, 16031, 16092, 16280, 15530, 18256, 16197, 21947, 16340, 16355, 13441, 15468, 15469, 13268, 15529, 16134, 16434, 16135, 9847, 15528, 16140, 15476, 15477, 21214, 4521, 14268, 18001, 15374, 17471, 17495, 15150, 16356, 16214, 16216, 17863, 15149, 16422, 15475, 18137, 14330, 14331, 19672, 19673, 15788, 15617, 22096, 16131, 16435, 15346, 24733, 15373, 16240, 16069, 16167, 18038, 16370, 17489, 17494, 18272, 18273, 16420, 13771, 16405, 13928, 13954, 15331, 18261, 17059, 17060, 16532, 17405, 17406, 18201, 16744, 16745, 16542, 16541, 16853, 18283, 17986, 18469, 18751, 18301, 18302, 18303, 16531, 21208, 16729, 16381, 17067, 18222, 18223, 17320, 19706, 17352, 18245, 18246, 17354, 18267, 17496, 20898, 20899, 20895, 18518, 18168, 18945, 18101, 20519, 18284, 17061, 23108, 18266, 18446, 18515, 18534, 28197, 18167, 21111, 20941, 24781, 35367, 19707, 34766, 18896, 18897, 25044, 20059, 24375, 29608, 19313, 22078, 21294, 26333, 26524, 16464, 18535, 16230, 9643, 21842, 22097, 18445, 20576, 21512, 22187, 5545, 20816, 22189, 18358, 22634, 16326, 25262, 25112, 4705, 16317, 2012, 19727, 4286, 24599, 24756, 18438, 23862, 20621, 26109, 33556, 33565, 25070, 26038, 25641, 1767, 25583, 3191, 20903, 5394, 21193, 26523, 26525, 23897, 27479, 27476, 24931, 4638, 26863; Motorcode: 20 6S 3, 20 6S 1/2, 25 6S 1/2, 30 8S 1, 6VDI, HDY Kat., UFZ, KDY,HDY Kat., G6BA, B5A, HDY, K6C, K6D, 156 A2.000, 141 C2.000, 156 A2.246, 156 A2.000, G6AV, A02, C27A1 V6, 4G93 Kat., 4G63 DOHC, 4G63 Kat., 4B10, 4AFE, F2G, B62, B67, BP, B3, 40 8S 1, 18 4E 2, L6A, E7J 706 Kat., E7J 745 Kat., E7J 742 Kat., AEK, AFT, B5252S Kat., AJ16, D16B2/D16Y3, 6G74 (DOHC), 6G74 Kat., 4G92, 4G92 MVV, BPZE, FP, D16A6, EJ18S, G13BA, G4EK, 25 6S 3, 18 4E 1, 135M, G13B, 4G64 Kat., B6, BP, 4G93 DOHC, R6E, 136M, D14A3, AMX, ATX, CDY, HDY, 4G92 Kat., EEB,EEO, KFW, K7M 720, G18A, JE, B5244T, B5252S, B5204S, 25 6S 3/4, SR20DEL, KFX, K5A, H3A, AKL, LFW, EJ16J, BC, FS, FSY8, X20SED, E7J 635, 156 A2.246, HFY, K6C/ K6D, KFW, 16 4E 1, AMU, H22A, KF..., B 16 LES, 178 D2.011, G16BBN, K4M 696, AUQ, ATC, K4M 704, H22A8, Sigma, 2112-10/16, 182 B6.000, FEKG, B4204T, B4184S9, K16-Rover, Rover-K14, K4M 766, B20Z1, 176 D2.011, T16 2.0 DOHC 16V, T16, K5A, 20 T4, G6, F4R 747, QG18DE, QG18DE, K4M 711, BBG, 1NZ-FE, BBJ, AGU, AUM, AEG, APK, AQY, K4M 708, F4P 773, AWP, 2112, 2112-70/76, K4J 712, K4J 713, HB, 1B, F5, 4G63, K4M 761, F4R 771, S6D, 5G, 3B PC, (A34), 4G64, AJ-V8, FE, K4M 760, K4M 762, K4M 764, K4M 788, D16Y8, BHF, ZJ, K 1.8T, K4M 792, 4G18 S4, K1.8T, SV8TS (A34), Delta V6, L6B, 21124, EJ15 (SOHC), 146 A2.166, D15B, L13A3, K4M 800, K4M 801, B5244S, B5234T3, A 16 LET, K4M 804, LFZ, LFZ, 6G72 (SOHC), CCSA, KFT, 21124, K4M 748, GA13DE, SQR480ED, TRITEC 1.6L, RFL, 4G63 SOHC Kat., F4R 813, K4M 856, E7J 773,710 Kat., EJ16E, M52, R6D, BFZ Kat., E6J 700, E6J 706, B5234T6, D7F 744, D7F 764, D7F 720, D7F 726, D7F 746, H, D15B2, 7A-FE, Z7X 753, R6D, 2RZFE EFI, 25 6S 5, K4M 830, B67, EJ25, E7J-A2, 21124, D16Z6, BPD, G13BBN, L15A7, 4AFE, TE, 25 6S 4, UFY, LFY, F4R, K4M, F4R 713, E-tech, EKG, F4R 746, G13B (SOHC), M13A, C35A, K4M 712, K4M 813, D15Y, L15A, 30 6S 3, EJ20E, 21129, 21179, 20 T4G, K7M 8..., 4B11, K4M 606, B4184S10, B4184S2, B4184S3; Baujahr ab: 04/1992, 02/1992, 09/1989, 04/1985, 03/1994, 01/1994, 06/1992, 01/1993, 06/1993, 10/1996, 09/1992, 07/1992, 08/1992, 12/1992, 05/1997, 08/1993, 07/1990, 03/1992, 10/1993, 03/1995, 09/1995, 07/1993, 01/1996, 01/1992, 10/1992, 01/1989, 06/1994, 02/1993, 04/1991, 11/1993, 07/1994, 05/1994, 09/1991, 08/1994, 11/1994, 06/1996, 10/1997, 04/1994, 10/1994, 07/1997, 09/1994, 02/1996, 10/1995, 09/1993, 04/1996, 05/1992, 07/1995, 05/2000, 08/1996, 10/1999, 06/2000, 02/1999, 08/1999, 12/1997, 07/1996, 09/1996, 05/1999, 12/1996, 01/1997, 06/1998, 03/1996, 05/2009, 11/2010, 01/1999, 06/1995, 11/1996, 04/1997, 08/1997, 01/1998, 06/1997, 09/1988, 09/1997, 12/1999, 11/1999, 11/2000, 04/1998, 02/1998, 11/1997, 03/1998, 10/1998, 05/1998, 10/2008, 09/1998, 02/2004, 08/1998, 09/2000, 03/2000, 06/1999, 04/2012, 11/1998, 12/2009, 10/2011, 02/2015, 06/2009, 06/2001, 01/2000, 04/1999, 03/1999, 09/2013, 09/1999, 04/2008, 08/2000, 02/2000, 07/2007, 09/2011, 05/2005, 03/2001, 01/2002, 12/2000, 09/2001, 04/2002, 09/2002, 01/2004, 10/2001, 07/2003, 09/2003, 03/2003, 01/2003, 08/2002, 01/2006, 04/2004, 05/2004, 09/2009, 03/2004, 10/2003, 10/2010, 06/2006, 11/2004, 03/2005, 12/2004, 10/2005, 11/2005, 09/2010, 04/2003, 09/2005, 05/2006, 02/2006, 01/2005, 04/2005, 01/2001, 08/1995, 02/2002, 07/2002, 04/1993, 01/2008, 03/1997, 01/2010, 09/2004, 04/2000, 07/2008, 12/2007, 03/2010, 07/2001, 02/2005, 03/2007, 10/2002, 10/2006, 09/2008, 05/1991, 01/2009, 02/2008, 05/2010, 11/2001, 10/2007, 04/2007, 12/2002, 11/1995, 10/2000, 11/2012, 02/2007, 02/2001; einzustellender Elektrodenabstand [mm]: 0,9; Ergänzungsartikel / Ergänzende Info 2: Elektrodenabstand muss für Gasbetrieb eingestellt werden; Fahrzeugtyp: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ; Motornummer bis: 14159540, 2533528; Fahrgestellnummer (VIN) ab: 00800001, YD 471565; Fahrgestellnummer (VIN) bis: 8N..X..015 500; Nennleistung [W]: 130; VW: Golf IV Schrägheck (1J1),Golf V Schrägheck (1K1),POLO (9N_),TOURAN (1T1, 1T2),GOLF VI (5K1),Transporter V Bus (7HB, 7HJ, 7EB, 7EJ, 7EF, 7EG, 7HF, 7EC),Passat Variant (3C5),Transporter IV Bus (70B, 70C, 7DB, 7DK, 70J, 70K, 7DC, 7DJ),GOLF PLUS (5M1, 521),PASSAT Variant (3B6),Multivan V (7HM, 7HN, 7HF, 7EF, 7EM, 7EN),Caddy III Kombi (2KB, 2KJ, 2CB, 2CJ),Transporter V Kastenwagen (7HA, 7HH, 7EA, 7EH),GOLF III (1H1),New Beetle Cabrio (1Y7),Golf IV Variant (1J5),Lupo (6X1, 6E1),Golf III Cabrio (1E7),Touareg (7LA, 7L6, 7L7),Caddy III Kastenwagen (2KA, 2KH, 2CA, 2CH),Golf V Variant (1K5),PASSAT (3B3),Transporter IV Kastenwagen (70A, 70H, 7DA, 7DH),SHARAN (7M8, 7M9, 7M6),PASSAT Variant (3A5, 35I),POLO (6N2),PASSAT Variant (3B5),Passat Limousine (3C2),Polo Schrägheck (6N1),Eos (1F7, 1F8),Bora Limousine (1J2),Bora Variant (1J6),Golf IV Cabrio (1E),PASSAT (3B2),Phaeton (3D1, 3D2, 3D3, 3D4, 3D6, 3D7, 3D8, 3D9),New Beetle Schrägheck (9C1, 1C1),Transporter IV Pritsche / Fahrgestell (7; AUDI: A4 Avant (8K5, B8),A6 Avant (4F5, C6),A3 Schrägheck (8P1),A4 Avant (8ED, B7),A3 Sportback (8PA),A3 Schrägheck (8L1),Q5 (8RB),A4 Avant (8E5, B6),A4 Limousine (8D2, B5),A6 Avant (4B5, C5),A4 Limousine (8K2, B8),A5 Sportback (8TA),A4 Avant (8D5, B5),TT Roadster (8N9),80 Limousine (8C2, B4),A6 Limousine (4F2, C6),A5 Coupe (8T3),A4 Limousine (8E2, B6),A4 Cabrio (8H7, B6, 8HE, B7),A2 (8Z0),A4 Limousine (8EC, B7),100 Limousine (44, 44Q, C3),TT Coupe (8N3),A6 Limousine (4B2, C5),A8 (4E2, 4E8),Cabriolet (8G7, B4),A8 (4D2, 4D8),80 Avant (8C5, B4),100 Limousine (4A2, C4),A5 Cabrio (8F7),A6 Avant (4A5, C4),Allroad (4BH, C5),COUPE (89, 8B),A6 Limousine (4A2, C4),A3 Cabrio (8P7),100 Avant (4A5, C4); MERCEDES-BENZ: C-Klasse Limousine (W203),A-Klasse (W169),B-Klasse (W245),C-Klasse T-modell (S203),C-Klasse Limousine (W202),SLK (R171),SLK (R170),CLK (C209),E-Klasse Limousine (W210),C-Klasse Sportcoupe (CL203),CLK (C208),S-Klasse Limousine (W220),E-Klasse T-modell (S210),CLK Cabriolet (A209),C-Klasse T-modell (S202),CLK Cabriolet (A208),S-Klasse Coupe (C215); OPEL: Corsa D Schrägheck (S07),INSIGNIA Caravan,Astra J Sports Tourer (P10),Meriva A (X03),Astra H Schrägheck (A04),Astra H Caravan (A04),ASTRA J,Corsa E Schrägheck (X15),Astra H GTC (A04),INSIGNIA,Vivaro A Kastenwagen (X83),Omega B Limousine (V94),INSIGNIA Stufenheck,Astra H TwinTop (A04),Astra J GTC (P10),Vivaro A Combi (X83),Omega B Caravan (V94),Calibra A (C89),Frontera B SUV (U99),Vectra A Limousine (J89),ASTRA J Stufenheck,Frontera A SUV (U92),Omega A Limousine (V87),Vectra A CC (J89),Senator B (V88),Vivaro A Pritsche / Fahrgestell (X83),Omega A Caravan (V87),Monterey A (M92),Monterey B (M98); BMW: 3 Touring (E91),3 Limousine (E90),3 Limousine (E46),5 Limousine (E60),1 Schrägheck (E87),5 Touring (E61),5 Limousine (E39),3 Touring (E46),3 Cabrio (E36),X3 (E83),3 Coupe (E46),3 Limousine (E36),3 Coupe (E92),X1 (E84),1 Schrägheck (E81),X5 (E70),Z3 Roadster (E36),5 Touring (E39),Z4 Roadster (E85),3 Cabrio (E46),3 Limousine (E30),3 Coupe (E36),3 Cabrio (E93),X5 (E53),3 Compact (E46),3 Compact (E36),7 (E38),5 Limousine (E34),1 Coupe (E82),7 (E65, E66, E67),3 Cabrio (E30),3 Touring (E36),6 Coupe (E63),7 (E32),5 Touring (E34),3 Touring (E30),8 (E31),6 Cabrio (E64),Z3 Coupe (E36),Z8 Roadster (E52); FORD: GALAXY (WGR),TRANSIT Kasten (FA_ _),TRANSIT Bus (FD_ _, FB_ _, FS_ _, FZ_ _, FC_ _),FIESTA III (GFJ),TRANSIT Pritsche/Fahrgestell (FM_ _, FN_ _),SIERRA (GBG, GB4),SIERRA Schrägheck (GBC, GBG),Escort VI Cabrio (ALL),Escort VI Schrägheck (GAL, AAL, ABL),Escort V Schrägheck (GAL),SCORPIO I (GAE, GGE),Escort VI Kombi (GAL, ANL),SCORPIO I Stufenheck (GGE),Escort Mk5 Cabrio (ALL),SCORPIO II (GFR, GGR),ESCORT '95 Express (AVL),SIERRA Kombi (BNG),Escort VI Limousine (GAL, AFL),Scorpio II Kombi (GNR, GGR),Escort V Kombi (GAL),SCORPIO I Kombi (GGE),Escort V Limousine (AFL),Territory SUV; RENAULT: Clio III Schrägheck (BR0/1, CR0/1),CLIO II (BB0/1/2_, CB0/1/2_),TWINGO I (C06_),TWINGO II (CN0_),MEGANE III Grandtour (KZ0/1),Scénic III (JZ0/1_),SCÉNIC II (JM0/1_),ESPACE IV (JK0/1_),KANGOO (KC0/1_),TRAFIC II Kasten (FL),Megane III Schrägheck (BZ0/1_),MODUS / GRAND MODUS (F/JP0_),GRAND SCÉNIC III (JZ0/1_),MEGANE II Coupé-Cabriolet (EM0/1_),LAGUNA II (BG0/1_),Scénic I (JA0/1_, FA0_),LAGUNA III Grandtour (KT0/1),TRAFIC II Bus (JL),MEGANE II Kombi (KM0/1_),KANGOO / GRAND KANGOO (KW0/1_),KANGOO Express (FW0/1_),MEGANE II (BM0/1_, CM0/1_),MEGANE III Coupe (DZ0/1_),LAGUNA II Grandtour (KG0/1_),KANGOO Express (FC0/1_),CLIO Grandtour (KR0/1_),MEGANE I Cabriolet (EA0/1_),GRAND SCÉNIC II (JM0/1_),LAGUNA III (BT0/1),MEGANE Scenic (JA0/1_),ESPACE III (JE0_),MEGANE I (BA0/1_),CLIO I (B/C57_, 5/357_),KANGOO BE BOP (KW0/1_),Vel Satis Schrägheck,MEGANE II Stufenheck (LM0/1_),TWINGO I Kasten (S06_),MEGANE CC (EZ0/1_),LAGUNA I (B56_, 556_),LAGUNA Coupe (DT0/1),MEGANE I Grandtou; SKODA: Octavia II Combi (1Z5),Fabia I Combi (6Y5),FABIA (6Y2),Octavia I Combi (1U5),OCTAVIA (1Z3),OCTAVIA (1U2),SUPERB (3U4),FABIA Stufenheck (6Y3),FELICIA II (6U1),Fabia I Praktik (6Y5),Felicia I Pickup (6UF, 6U7),FELICIA I (6U1),FELICIA I Kombi (6U5),FAVORIT (781),FAVORIT Forman (785),FAVORIT Pick-up (787); FIAT: GRANDE PUNTO (199),PUNTO (188),DUCATO Pritsche/Fahrgestell (230),DUCATO Bus (230),DUCATO Kasten (244),DUCATO Pritsche/Fahrgestell (244),Seicento / 600 Schrägheck (187_),STILO (192),Panda Schrägheck (141_),DUCATO Kasten (230L),BARCHETTA (183),DUCATO Bus (244, Z_),PUNTO (176),QUBO (225),COUPE (FA/175),STILO Multi Wagon (192),FIORINO Kasten/Kombi (225),CINQUECENTO (170),Uno Schrägheck (146_),PUNTO Cabriolet (176C),Linea (323_, 110_),BRAVO I (182),TIPO (160),BRAVA (182),ULYSSE (220),FIORINO Kasten (146),MAREA Weekend (185),PALIO Weekend (178DX),MAREA (185),TEMPRA (159),TEMPRA S.W. (159),FIORINO Pick up (146),Siena (178_, 172_),PALIO (178BX); SEAT: Ibiza III Schrägheck (6L),Leon Schrägheck (1P1),Leon Schrägheck (1M1),Altea (5P1),AROSA (6H),Altea XL (5P5, 5P8),Exeo ST (3R5),Alhambra (7V8, 7V9),Toledo II Limousine (1M2),Ibiza II (6K1),Exeo Limousine (3R2),Cordoba Limousine (6L2),Cordoba Limousine (6K1, 6K2),Toledo III (5P2),Inca (6K9),TOLEDO I (1L),Cordoba Vario (6K5),Ibiza III (6K1),Cordoba Limousine (6K2); 9807B5617W, 101654016, 9807B5617W, 9807B561BW, 9807B561CW, 1822A002, MN163236, MN1632364, 32017042, 32017044; Zündkerzen,Kerzen,Zuendkerzen