Crowfoot wrenches are used in hard to reach, restricted access situations where a standard wrench or ratchet cannot reach. Anti-Slip Design Open End (ASD) has locking grooves that help prevent the wrench from slipping off the fastener when turning. The arched surfaces are designed to spread the contact forces over a greater area and they keep the loads off the corners of the fastener which helps prevent fastener rounding. Broad size range ensures the right tool for the application will be available. Typically used in lower torque applications. Full Polish finish provides corrosion resistance and easy to clean surfaces. Locking hole feature helps keep the crowfoot wrench engaged on the extension during use reducing downtime due to detachment of crowfoot in awkward spaces. Use with locking extensions to reach into spaces too small for a mechanic's arm or where the fastener is out of site. Locking hole on 3/8" drive crowfoot wrenches available on fractional openings 1" and larger.