The Dial 6539 39" Precision Engineered V-Belt is a highly-reliable, durable product from Dial. These V-belts are standard type-A high quality. They measure 1/2" wide x 5/16" thick and are designed for fractional horsepower motors. To determine belt size: measure the current belt's circumference and choose nearest size. If a variance exists, choose a slightly larger belt. Belts may be tightened by an adjustable motor pulley and by adjusting the motor on the tension bracket.