Precision and hardend Titanium coating wear-resisting non-magnetic and the inside structure also has special material, it is non-magnetic Shank: 10mm (shank diameter tolerance H7 ) suitable speed: 400--600rpm Probe: 4mm and 10mm Biggest diameter of edge finder: 20mm Colour: gold Material: high-speed steel Package Contents: 1 x edge finder PLEASE NOTICE--This edge finder is special, the biggest diameter is 20mm, it is bigger than the normal , so the edge finder is more steady and high precision. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.