Product Description2-1/2"" drop in/open style distribution rings are used when support is needed fir cables that must remain accessible. Garvin Industries distribution rings have a smooth surface that prevents cable damage. They are made of durable and long lasting die cast aluminum. Application:These distribution rings are used when support is needed for cables that must remain accessible. Advantages: Garvin Industries distribution rings have a smooth surface that prevent cables from being damaged. They are made from durable and long lasting die cast aluminum. Field Names: D rings, distribution rings, backboard D rings, open D rings.