Designed for all-day use, these over-ear hearing protectors have memory foam ear cushions for comfort and an adjustable vented headband. They use specially developed technologies to limit volume output to 85dB to protect you from harmful noise, automatically lowering the volume when the circuitry detects a sudden loud sound and then returning to a normal listening level. Compatible with Bluetooth 4.2 and Siri and Google Voice, they let you maintain up to two simultaneous active connections (up to 30'). The noise-isolating microphone allows you to clearly communicate over either channel in noisy environments while remaining aware of your surroundings. Large volume control buttons let you easily adjust the Bluetooth connection and the ambient output independent of one another. The rechargeable battery (USB cable included) provides up to 11 hours of talk time or can be switched out for three alkaline AAA batteries (you supply) to power up to 22 hours of connection. An auto power-off after 4 hours without Bluetooth connection helps to preserve battery life. ANSI-certified (25dB NRR) and OSHA-compliant with a durable IPX4 rating for perspiration and water resistance.