Wera 851/1 Z Phillip #1 bit for 1/4" hex drive is designed for hard metal materials. Tough viscous bits allow an increased amount of peak torque necessary for hard materials, preventing the breakage of tips. Ideal for hard materials such as sheet steel or metal. Partner with Rapidaptor universal bit holder for quick one-handed bit exchange. German engineered. Bit dimension: 1/4” hex drive; PH1 x 1". Wera – The Best Tools For The Job!