Drive compatibility: Compatible with inch drive or 21 mm Versatility for tightening and loosening: Extends a wrench to create more leverage. Designed to fit on different wrenches to loosen stubborn rusted bolts and screws or to tighten them. To switch between tightening and loosening, simply place it on the opposite side of the wrench Steel construction: Robust steel construction prevents slipping or rounding of the drive. Heat-treated steel provides strength, and the design functions as a Drop Body Wrench Adapter Rust protection and durability: Heat-treated steel with a protective coating to prevent rust. Performs well on rusty bolts and screws and is resistant to daily wear for years of use Use scenarios: - Loosening stubborn rusted bolts in automotive or machinery maintenance where extra leverage is needed - Tightening or loosening fasteners in tight or hard-to-reach spaces by using the adapter on the opposite side - General DIY tasks involving rusty screws or bolts in outdoor equipment or furniture need for frequent use