Package Includes--You will receive 15 x O-Ring: wire diameter 4mm, 15 x pin: 3 x 25mm, wide range of uses. High-quality Material--Accident proof ring and pin. Flexible O-rings and sturdy pins; made of high-quality rubber and stainless steel, tough, durable and long service life. High Strength--When used on impact wrenches, they can guarantee long-term work. Can be used to secure 1/2" sockets on other models, with similar style 1/2" drive. SMALL TIPS: Pin must be through the 2 hole of socket and then use O-ring to secure. Wide Application--Suitable for scaffolding, impact wrench, needle roller bearing, automobile sealing strip, radiator hose, rubber pad, etc. Suitable for electic and airtools. Tips--Please confirm the size before placing the order and purchase it correctly. You can contact us via email at any time if you have any questions, we will resolve your problem without hesitation until you are satisfied.