【Note:】 Specifically designed to fit Milwaukee type 1/2" cordless impact wrench Does not fit DeWalt or other cordless tools 【How to Install New O-Ring:】 Place retaining ring into install tool recess, Insert anvil into retaining ring at a 45Push and bring the anvil perpendicular 【High Quality:】 The o-ring is made of high-quality rubber, which is not easy to break; the retaining rings is made of carbon steel, which is wear-resistant 【Package Includes:】 10 Sets 1/2" Impact Wrench Retainer rings & O-ring