Use this chuck key with to quicken tool changes on your #30, #30H, #30SJ & #25C handpieces. Also for hand-held power and cordless drills, drill presses, power drills, flexible shaft grinders, and other power tools. It is made from steel. Key size of 1/8" ( 3.175 mm). A great choice replacement for lost or damaged chuck keys PRODUCT SPECIFICATIONS - Steel Body - Key Size: 1/8" - Use this chuck key with #30, #30H, #30SJ & #25C handpiece Foredom handpieces