AccusizeTools - 5C 5" Collet Chuck Plain Back for Lathe Machine, 0269-0010 Outside Diameter: 5". Max. RPM 6000. Accuracy: .0006 TIR. Weight: 10.44 lbs. Plain Back, Recessed 3.740'' x 0.184'' Deep Plain Back, have to shoose proper back plate to connet with your machine. Should be used with back plate (adapter) to connect with your specific lathe spindle. Can use any size 5C Collet: Round collet :1/16 ~ 1-1/8"; Hex collet:1/8" ~ 7/8"; Square Collet:1/8" ~ 3/4" Scroll and pinion design just like 3-jaw chuck, operated with chuck key. Scroll & pinion precision machined and hardened.