Stanley Proto J5330MCF 1/2-Inch Drive Full Polish Metric Crowfoot Wrench, 30mm 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) 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 Broad size range ensures the right tool for the application will be available Typically used in lower torque applications