Panther Drive Belts Rear Drive Belt - 1 1/8in - 128T Improved RPP Panther Design Feature ULTRA-CORD tensile members and the Able compound ULTRA-CORD does not stretch or shrink, thus reducing the strain on bearings, shafts, and other drive components ULTRA-CORD resists degradation and moisture to give you longer belt life The Able compound, an advanced polymer, resists tooth shear, adding to the belts stability