KNUCKLEBUDDY adds 10" to your existing wrenches for maximum leverage. Its 15,30 & 180 degree angle feature allows you to loosen and tighten nuts and bolts in hard to reach areas. KNUCKLEBUDDY works with both SAE and MM sizes up to 1" or 25mm. Its versatility allows it to be used with other tools. (I.E Crescent wrench, Allen wrench, ratchets and more). KNUCKLEBUDDY comes with a Lifetime Hassle Free Warranty - We stand behind our product. If KNUCKLEBUDDY breaks or becomes inoperable well replace it! That easy! No hassle!