High-Strength Ultra-Quiet timing belts also known as GT profile belts, belts with curved teeth minimize vibration and noise output. The teeth distribute pressure uniformly, so they wear evenly and last longer. Close engagement of the tooth and pulley offers more precise timing in heavy-load systems than trapezoidal teeth and HTD belts. Belts are neoprene, which is flexible and operates quietly. The fiberglass reinforcement on these belts add greater durability.