The Whirlpool WPY312959 Drum Belt transfers motor power to rotate the dryer drum during drying cycles. This replacement belt fits around the drum and connects with the motor pulley and idler assembly, allowing the drum to turn at the required speed while the dryer runs. A worn, stretched, cracked, or broken belt can cause the drum to stop rotating, produce unusual sounds, or result in ineffective drying. Replacing a damaged belt can restore proper drum movement and support consistent drying performance.