The Dial 6566 66" Precision Engineered V-belt is manufactured for your evaporative or swamp coolers. If the belt you have now is showing signs of cracking or wearing out, it is always recommended to replace it before it slips or snaps. This can also be used on motors that operate in fractional-horsepower machines like alternators, air compressors, water pumps and many more. It is created with a form that assists it to remain inside the pulleys while the belt is running. The Dial 6566 66" Precision Engineered V-belt will endure for a long period of time, so it is a good choice to have them put on your swamp coolers for consistent operation. Furthermore Dial 6566 66" Precision Engineered V-belt is a low-maintenance belt and a very reliable product you can trust. Setting up or replacing the V-belt is a piece of cake, it's merely a matter of how quickly you loosen the bolts of your motor to release tension. In order to work effectively, you just need the belt to be aligned straight to the pulleys. As for the belt lengths, V-belts will come in handy offering you sizes ranges from 20 inches to 100 inches that will pair up with your machines with this specific model measuring 66 inches. 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 belts 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.