Internal fiberglass tensile cord provides flexibility, usage life, resistance to elongation and high torque strength.D660H787 DAndD Powerdrive H Double Replacement Timing Belt Of Teeth: 132, Material: Neoprene, Series: H, Pitch: 1/2 InchFEATURES And BENE FitsPrecision-formed trapezoidal or squared bottom elastomeric teeth on both sides of the timing beltDual timing belts provide equal load carrying capacity from both sides of the belt.