Treadmill Doctor replacement belts are made of durable PVC top coat and a polyester blended backing. Most belts from other manufacturers are thicker and less pliable, causing a higher strain on the electrical components on the treadmill and increasing the risk of damage to those parts. Treadmill Doctor belts are pre-lubricated for worry free installation and no maintenance for 6-8 months. Treadmill Doctor offers replacement belts for several top brands including NordicTrack, Proform, Exerpeutic, GoPlus, Sunny, Sole, Precor, True, Confidence, Smooth, Image, Weslo, Reebok, Epic, Golds Gym, Freemotion and Healthrider Treadmills.