Round belts and o-ring belts are light-to-medium duty belts used in power transmission applications. Round belts are solid or hollow and vary in terms of weight and size. They use friction to stay in contact with round belt pulleys and must be stretched or elongated to provide proper driving tension. O-ring belts (endless round belts, endless drive belts) also vary in weight and size, but do not require a belt tensioner. They can be used with both round belt pulleys and V-belt pulleys. Most o-ring belts are made of materials that are resistant to chemicals and compounds such as oxygen, ozone, oils, and grease. They can be cleaned easily and resist abrasion and marking. Belts that are heat-sealed do not require tooling changes. Most round belts and o-ring belts are between 1/16 in. and 3/4 in. wide and at least 3 ft. long, depending on the size of the cross-section. Some products have tensile strengths of up to 8,000 psi and a temperature resistance that ranges from
- 60° F to 225 F°.