Wide applicability: Our wrench expander is 1/2 inch or 21mm hex drivers.This key extension adapter is ideal for professionals. Tighten and loosen the washer: Designed to extend the key with another key to create more leverage. Suitable for different wrenches, loosen or tighten stubborn rusty nuts and bolts, easier to remove, save effort. To switch to tightening or loosening, you just have to put it on the other side of the key. Durable steel construction: The sturdy construction of this master Key extension adapter prevents the drive from slipping or finishing.Heat-treated steel construction makes the key extension strong and durable. Forge body key adapter. Antirust material: Heat treated steel,protective coating to prevent rust.This universal wrench works well on rusty nuts and bolts.Resist frequent corrosion and fading.Durable and will last for years. Great key extension tool: Master Key Extension adapter saves you time and effort.Ideal for adding more lever heavy duty nuts and bolts,and access to hard-to-access areas. Product name: Wrench expander Type: Wrench Set Model Number: Wrench converter Colour:black Material:Carbon Steel Package Contents: 1 * Wrench expander Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.