Oatey 33951 Insulating Pipe Clamp, 3/4-Inch Designed to eliminate notching and wrapping of pipe when running water lines through framing. Reduces water line noise and vibration. No corrosion  made of durable, low-density polypropylene (gray color). UPC listed. Eliminates contact between the pipe and framing surface thereby reducing transmission of water line noise No corrosion  made of durable polypropylene (gray color) Ribbed design allows faster cooling and pipe expansion and contraction Can be used on hydronic systems