Fits copper, CPVC, PEX, and polybutylene tubing. Nail preloaded in clamp. Ribbed design insulates against water line noise. Clamp is made of durable polypropylene (grey color). 12 per bag. No. 33910: Type: Insulator, Size: 1/2″, Material: High Impact Polypropylene Plastic, Pkg Qty: 12, Package Type: Bag No. 33912: Type: Insulator, Size: 1/2″, Material: High Impact Polypropylene Plastic, Pkg Qty: 12, Package Type: Bag No. 33911: Type: Insulator, Size: 3/4″, Material: High Impact Polypropylene Plastic, Pkg Qty: 12, Package Type: Bag No. 33913: Type: Insulator, Size: 3/4″, Material: High Impact Polypropylene Plastic, Pkg Qty: 12, Package Type: Bag