internal circulation,double nut,flange type,preloaded model:FFZD5020-4 model:FFZD5020-4diameter:50mmlead:20mmnumber of circles:4length:as customer requestaccuracy:P1(0.005mm per 300mm) P2(0.008mm per 300mm) P3(0.012mm per 300mm) P4(0.016mm per 300mm) P5(0.023mm per 300mm) P7(0.052mm per 300mm). If customer has special request ,please send us the drawing.we will make as customer's drawing if we ...