AerosmithŽ’s Sure-ConŽ Concrete Screws are designed to meet the demands of most medium to light duty applications. The screws are hardened and come with a blue environmental coating which allows them to be used in dry interior applications and some exterior applications. The product can be used in concrete, block and brick and manufactured with either a hex washer head or phillips head. Just pre-drill a hole using a proper size concrete drill bit and run anchor into pre-drill hole. Each box of screws contains one drill bit.