This Power Transmission Fractional Horsepower Belt has an inside length of 18″ and an outside length of 20″ and a thickness of .31″. It is recommended that all Power Transmission V-Belts should be replaced as complete sets. Additionally, the industrial power transmission fractional horsepower belts should not be reused. Please contact Bearing & Transmission Supplies for further information on all your power transmission supplies at (800) 621-0237.