.75in ceiling drop - Office White. HellermannTyton's low voltage TSR surface raceway system is a one piece latching duct designed to contain, route and protect wire and cable when it is not feasible to run it within the wall. It is manufactured from a 94 V-0 PVC and features a superior adhesive which conforms to most any surface. Designed with a flexible hinge, the raceway allows numerous openings without creating discoloration or stress cracking. The self-locking, hidden positive latch allows for quick re-entry as well as secure installation of wire and cable.