Primo offers replacement belts in two strength. The normal HTD belt replaces the belt that is normally supplied with the Primo belt drive kits. There is also a Kevlar quality belt available. The Kevlar belts feature a kevlar cord layer that has exceptional strength compared the cord layer in the HTD belts. Kevlar belts are highly recommended for use with high performance and big cubic inch motors. Primo Kevlar belts are used on the primary of the 600 + Horsepower Drag-Bikes of Ton Pels and many others.