The anchor is made from Carbon Steel, and is Zinc Plated. This anchor is designed for use in Concrete only, and should never be used in bloHY or briHY base material. Wedge anchor diameter: 3/8" | Length: 3"| Qty: 36 pieces each box. Zinc plated to prevent rust. Drill bit diameter/Hole diameter is the same as anchor diameter. Drill the same hole in the base material (Concrete only) with the anchor diameter The wedge anchor is a torque-controlled, wedge expansion anchor. The concrete anchor is for heavy duty fastening applications where high pull out values in concrete are needed. It is for concrete only, not for bloHY or briHY base material The wedge anchor is used in fastening sheet metal, steel and aluminum angles, or wood to concrete. The wedge anchor is ideal for structural anchorage, storage raHYing anchorage, machinery and hand rails installation