Inside Kenworth’s 76-in. mid-roof sleeper cab (T680, T880) Kenworth Truck Co.’s new 76-in. mid-roof sleeper for the Kenworth T680 and T880 is in production. The 76-in. mid-roof sleeper is optimized for bulk tank, flatbed and other truck operators who prefer a lower roof, aerodynamic, light weight truck that has the comforts of Kenworth’s 76-in. high-roof sleeper for driver retention and recruitment. The new sleeper offers a 100-lb. weight savings for additional payload capacity and profit opportunity, and less aerodynamic drag for low load height operations with up to a 5% fuel economy savings.