Dryer cycling thermostat with internal bias heater, L155-25. If the dryer won't heat, it is unlikely that this thermostat is causing the issue, as the thermal fuse or thermal cut-out normally fail first.
High-limit thermostat, 2 wire, 250 degree limit, 60 degree cool down before reset. The high-limit thermostat cuts off power to the dryer if it overheats. If the thermostat has tripped, the dryer will not heat. To determine if the thermostat is defective, use a multimeter to test it for continuity.