Product Description 10pc Hex Driver Bit SetHollow TipSAE 08051 10pc set made from superior grade S2 Chrome vanadium alloy steel, Hardened and tempered for durability. Genuine trade quality, these bits feature a 1/4″ Hex Shank for use in cordless driver and drills. Features Security tip: These bits feature a hollow in the end so you can also use them for security type screws. S2 Chrome Vanadium Bits Industrial Grade Made from Silicone Chrome Vanadiumalloy steelour Bits are hardened toan exact standard sizes:5/64,3/32,7/64,1/8,9/64,5/32,3/16,7/32,1/4″ & 5/16