... 4.58-60 hardness 1.Item: impact driver bits,impact screwdriver bits,power driver bits2.Size : H1/4"*25mm*PH33.Application ... : screwdriver bits, power bits, pneumatic power bitsS2 material4. finishing: Sand blasting5. ... ,Chrome electro-plating, manganese hypophosphite both them available for us High quality sand blasting impact screwdriver bits