Bridgeport 941-AL 1/2 IN Clamp Back, Alum, Box of 50
https://nsiindustries.us.com/product/clamp-back-1-2-aluminum/
Bridgeport Clamp Backs are used to provide space between mounted conduit and mounting surface. Designed to be used with malleable or aluminum straps. Aluminum construction offers a lighter weight and more cost-effective solution in less harsh environments.