1/2" Drive Or 21 MM Hex DriveOur wrench extender is compatible with 1/2 inch drive or 21 mm hex drive. This wrench extender adaptor is great for professionals. When working on heavy equipment as a technician you may need to have these. Both Tighten & Loosen WaysDesigned to extend wrenches with another wrench to create more leverage. Used on different wrenches to loosen or tighten stubborn rusty nuts and bolts, which can be removed more easily and save effort. Change to tighten or loosen, you just need to put it on the other side of the wrench. Durable Steel ConstructionHeavy duty construction of this universal wrench extender adapter prevents drive from slipping or rounding out. The heat-treated steel structure makes the wrench extension strong and durable. Drop forged body wrench adapter. Rust Proof MaterialHeat treated steel, the protective coating prevents rust. This universal wrench extender can work great on rusty nuts and bolts. Resists daily corrosion and tarnishing. Durable for years of usage. Great Wrench Extender ToolThe universal wrench extender adaptor can save your time and effort. Great for adding more leverage on stubborn nuts and bolts and for getting into hard to reach areas.