1.Material:65Mn 

2.Hardness:clamping part HRC55-60 elastic part HRC40-45  
3.Types: 5C ROUND COLLETS,5C SQUARE COLLETS,5C HEX COLLETS 
4.Model:imperial and metric
4.This unit is applicable to all sorts of lathes,which spindle taper hole is 5C,such as automatic lathes,CNC lathes etc.