Check the listing for details. Pyramex Level Dependent Electronic Hearing Protection Earmuff PM4011. Condition: New. Listed at 32.95 USD. Pyramex Level Dependent Electronic Hearing Protection Earmuff PM4011 Pyramex Level Dependent Electronic Hearing Protection Earmuff is a level dependent electronic hearing protector with built-in microphone and electronic amplification circuits, which can amplify ambient sound. This Pyramex Ear Muff features a soft, padded head band for all day comfort and foam-filled padded ear cups that fit securely and comfortably over the ear. The Level Dependent Electronic Hearing Protector PM 4011 by Pyramex automatically shuts down the electronic function when ambient sound exceeds preset safety level (83 dB). The hearing protection earmuff is ideal for noisy industrial environments as well as outdoor activities, such as hunting and amplifies surrounding voices, important signals and warnings.