This Bipolar Clutch Tool fits on 50cc-125cc horizontal engine ATV Dirt Bike and Go Kart Inner Diameter(upper):19mm(0.75”); Inner Diameter(under): 23mm(0.9”),Total length: 60mm,Outer Diameter(upper): 26mm,Outer Diameter(under): 31mm, Clutch Hub Nut Spanner Tool Fit Model: Honda CRF50, XR200 1980-1984 XR200R 1981-1994 XR250L 1991-1994 XR250R 1986-1994 Honda CRF50 , Z50 ,XR50 ATC70,ATC90 C70 ,CL70 ,CRF70,CT70 SL70 ,TRX70 ,XL70 ,XR70 TRX70,TRX90 TaoTao, Buyang, Coolsport, NST, BMX, Kazuma, Roketa, Baja, Jonway, Coolster, Kinroad,SSR, Hensim,JCL,BMS,NST,Peace,Lance,Jetmoto Supermach, etc. Size: Total length: 60mm Outer Diameter(upper): 26mm Inner Diameter(upper): 19mm Outer Diameter(under): 31mm Inner Diameter(under): 23mm package Included: Bipolar Clutch Tool