Package: 200pcs rubber pin backs, enough quantity for your own use or to share with your family and friends. Material: Made of rubber material, soft and lightweight, sturdy and durable. These rubber pin keepers offer a good grip of pin, fastened firmly and not easy to fall off. Size: Diameter: Approx 10mm; Height: Approx 8mm. Each pin back has a hole which is compatible with the tie tack pin. The rubber pin backs are only compatible with pins with a thickness of 1.2 mm , it can't fasten if the pin is too slim. Purpose: These locking pin backs keep the pin from moving around. The soft rubber pin backs effectively isolate sharp metal pins and ensure they remain in place. Wide Application: Great for lapel pins, tie tacks, service bars, badge, name tags, DIY jewelry making, etc. Can be used on purses, bags, jackets, shirts and so on.