Size: M3-M8 M5-M12 *Alloy steel,hardened.CR-plated. TAP WRENCHAll collets are made according to DIN6499B standard1.threading or drilling 2.M3-M6, M3-8, M5-10, M6-12 3.package: blister card 4.material: carbon steel*Alloy steel,hardened.CR-plated.package:carton box or plastic boxRegarding to detail of Tap wrench, please see our web sit.