Master Mechanic, 23/64″ x 4-7/8″, High Speed Steel With Cobalt Drill Bit, 135 Split Point Design With 4 Cutting Edges Allows Quick Penetration & Eliminates Walking, 8% Cobalt Content Provides Heat Resistance & Delivers Maximum Cutting Efficiency At Temperatures In Excess Of 1000&degree. F., Recommended For Drilling In Hard Metals Such As Heat Treated Steel, Stainless Steel, Chrome, Manganese Steel Plus Titanium & Armor Plate, Carded.