Dryer drum drive belt. The belt is flat, 92-1/4 inches long, 1/4 inch wide and has 4 ribs and 3 grooves. It replaces many other belts, including some with 5 ribs and 4 grooves. If the drum does not turn, but you can hear the motor running then there is a good chance the belt has broken.
Dryer lint filter (lint trap). Your lint filter should be replaced if it is torn or damaged in any way.
Dryer drum drive motor assembly. If the dryer does not start the motor could be bad. Before replacing the motor the door switch and thermal fuse should be tested to determine if they are defective.
Idler pulley wheel
Terminal block for main power cord