Triple Corner Ground Cable Roller Pulling Roller with Aluminum Alloy Wheels 1.The Cable Rollers that are available from LS are specifically designed for either Trench or Duct applications. Trench rollers are lightweight, for narrower applications, designed to lay on the ground and protect the cable from the surface.. 2.Duct rollers are designed to be placed at the entrance to a duct so the cable is protected from the rim and corner, to ease the cable in and avoid damage