Brand new chain roller tensioner with metal roller and spring Fit most 110cc 125cc 150cc 200cc 250cc ATVs and go karts compatible with 420, 428, and 530 chain Fit almost all Chinese and Japaneses brands Diameter of bolting hole: 10mm (weld on a 10mm or 3/8″ stud); Diameter of roller: 30mm; Length of roller: 35mm This is a brand new chain roller tensioner with metal roller andspring.Fit Models: most 110cc 125cc 150cc 200cc 250cc ATVs and go karts compatible with 420, 428, and 530 chain almost all Chinese brands, such as Blade, Kinroad, Twister Hammerhead, Carter Talon, Dazon, Roketa, DUNE 150, Baja 150 kart, Kasea, KPX, SUNL, Aimex, Alpha sports, Avanti, Bam X, Baotian, Bashan, BMS, BMX, Boreem, Eagle, CF Moto, Cross Runner, Cool Sports, Diamo, E Ton, Eagle, Fushin, Fly, GMI, Hensim, Hi-bird, Baja, Ice Bear, Jackel, Jet Moto, JCL, Taotao, Peace, JM Star, Jonway, Kazuma, Keeway, KMD, Kymco, Lance, Lifan, Linhai, Loncin, Longbo, Fuxin, Maxtrade, MDI, Meitien, Motofin