产品描述：
EAR Push-to-Listen Ear Defenders
When workers lift their ear defenders, they lower their protection. Just push the button on the PTL muff and speech and sounds outside can be heard inside - clearly and safely. After 30 seconds the muff automatically returns to its full protection. The push-to-listen feature is in one ear cup only, the other is standard protective style.
Uses 1 x 1.5V AA battery - estimated life span about one year.