The Glendinning under Coach Guide roller allows for easy installation through the floor or any compartment allowing power cable or water hose to slide easily around sharp corners. Also allows you to close your storage bay doors when the power cable is extended if mounted through the floor of the coach. The undercoach roller assembly has 6 separate plastic rollers to protect the cable as it passes through the bottom of the storage bay. It is secured to the bottom of the coach with 6 self-tapping screws - 1 inch long. Total Diameter of the Roller is 6". Total diameter: 6""