Ball contact point for use with Brown & Sharpe Interapid series dial test indicators . Ruby ball tip for light weight, wear resistance, stability with changes in temperature, suitable for delicate and silicon carbide surfaces, and non-magnetic and non-conductive properties for use in Electrical Discharge Machining (EDM) processes. M1.6 thread . Package:1x ball contact point. Ball contact point has an M1.6 thread size, and is designed for use with Interapid series inch dial test indicators. Carbide contact points are resistant to wear and magnetic fields.Ruby ball tip for light weight, wear resistance, stability with changes in temperature, suitable for delicate and silicon carbide surfaces, and non-magnetic and non-conductive properties for use in Electrical Discharge Machining (EDM) processes.