Proto crowfoot wrenches are mainly designed for low-torque applications and for use in hard-to-reach areas where a standard wrench or ratchet cannot reach. These wrenches feature anti-slip design (ASD) open end with patented locking grooves to securely grip fastener and avoid slipping while turning, and arched surfaces to evenly distribute the contact force over a broader area. They also have a locking hole to keep the wrench engaged on the extension, which helps in minimising the overall downtime due to repetitive detachment. The locking hole allows you to use this crowfoot wrench with locking extensions to reach into confined spaces. These Proto wrenches are also available in flare nut head style with 6- or 12-point box ends for use with hex nuts and fittings.