The Howard Leight Impact In-Ear Electronic Ear Plug is equipped with passive hear-thru technology and a noise rating of 29 dB. This model includes a separate hear-through volume control, allowing for realistic and natural sound awareness. The ear plugs are powered by a rechargeable 200mAh lithium battery, offering a runtime of 50 working hours after a charge time of 2 hours.Key FeaturesSeparate Hear-Through Volume Control: Adjusts the level of ambient sound for enhanced situational awareness.9mm Dynamic Range Speaker: Provides clear audio quality with a natural sound experience.USB-C Rechargeable: Easily recharges with a USB-C connection for convenience.Moldable Earhook: Designed for a customizable fit to enhance comfort during extended use.