Precision ground and hardened.This collet nut is a great replacement for the broken part.For use with ER32 Spring collets. Specification:Product Name : Collet NutsModel : ER32-UMStandard: MetricOverall Size:50 x23mm/ 1.97" x 0.91" (D*H)Thread Size: M40x1.5mmHole Diameter: 27mm/ 1.06"Material : Cast SteelPackage Content: 1 x Collet Nuts