Roll-top roll-off sludge containers from Custom Manufacturing store and transport a wide variety of waste. They have continuously welded seams, a fully gasketed rear door, a knife-edge seal, adjustable hinges, ratchet binders, secondary release grab handles located on the bottom side of the door, and 3/16-inch-thick walls and floor. Each lid measures 5 by 7 feet, with a 1- by 2-inch closed-cell gasket. One lid rolls to the bulkhead end and one rolls to the rear door end, leaving access to the center of the container. Units can be customized with either a top- or side-hinge rear door. 405/692-6311; www.custommanufacturing.us.