The Radians CSE10BX Tactical Electronic Earmuff amplifes low level sounds while protecting against harmful noise. Excellent hearing protection for all hunters and shooters. Listen to your favorite smartphone or MP3 device with the added input jack. Compact folding feature allows for easy storage. Product Features Electronic compression Amplifies environmental sounds Dual microphones for optimal sound reception Compact folding feature Adjustable headband Input jack with patch cable included for MP3 or smartphone devices NRR 23 dB