This is a sunstar 37 tooth rear sprocket. Looks just like the OEM ORIGINAL. Also included is a new front spk and CORRECT LENGTH 420 chain with a connector link. @ Chain_&_Sprockets Z50A AND Z50R LOOK_CLOSE 1/19A (50c/sSET) temp out of stock 50c/sSETPICK_YOUR_MODEL_AND_YEAR: Z50A&R_68_TO_81_SET_12T/37T/76L=9A/Y3005/76LZ50R_82_TO_87__SET_13T/37T/76L=17A/9A/76 @ Z50A REAR SUNSTAR (!!SPROCKET_ONLY!!) 1968_TO_1987 7/20W (9A_REAR_ONLY) 9A_REAR_ONLY @ Z50R 1988_TO_99 37TOOTH_REAR SPROCKET 420_CHAIN_TYPE 1/20W (94C) 94C @ *SPROCKET RETAINER PLATE FRONT Z50'S 1968_TO_1981 23802-045-670 7/20M (R2007) R2007 @ *LOCK PLATE FR SPK Z50R'S_82_TO_87 ATC70_82_-_85 TRX70_ALL 23802-041-010 1/21A (R2202) R2202 @ *LOCK_PLATE FR._SPK. (CT70_69_94) (ATC70_74_81) (Z50R_88_99) (ALL_C70'S) (ALL_PASSPORTS) 1/20A (R2026) R2026 @ *BOLT FRONT SPROCKET LOCK PLATE FITS Z50'S (81_AND_OLDER) ATC185/200 AND MANY OTHER HONDA'S (SOLD_EACH) 90084-041-000 1/21M (R2006) R2006 @ *BOLT_FRONT SPROCKET LOCKING_PLATE (6x8 MM) FITS ALL BUT (Z50 81 AND OLDER) 92101-06008-0A 1/22A (53D) (53D)