Tapping Adapter, Tap Size 5/16 in, Tap Square Size 6.05mm, Compatible with Product Type K-Series Double Angle Collet Chucks, Coolant Fed Non-Coolant Through, Features Design of Slots in Back of Collet Acts as a Drive for the Tap Square;Industry Standard Erickson Double-Angle Collet System;Provides Positive Drive for Tapping Applications