Proto J49001CF Crowfoot Socket Wrench Set, 3 8 in Drive, SAE, Open End, 43 PC 6B956 Recommended Housing Bore 35 Recommended Housing Bore 35 Industry Number BX93 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 which helps prevent fastener rounding Additional Features: 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 small spaces or where the fastener is out of sight Locking hole on 3 8" drive crowfoot wrenches available on fractional openings 1" and larger Crowfoot wrenches are used in hard to reach