(4L670) DAYTON V-Belt: 67 in Outside Lg, 0.5 in Top Wd, 5/16 in Thick4L section V belts are light duty belts for fractional horsepower (FHP) applications. They have a nominal top width of 1 2" and a nominal thickness of 5 16" (actual dimensions may vary slightly). FHP V belts, identified with an "L," are single belts used on drive systems that are typically operating at 3 HP or less. These V belts are often used in HVAC equipment and appliances.