Ultra bright: Features an LED light with two brightness settings, high light (500 lumens) and low light. Rechargeable: Charges via a USB cable (included), requires 5.5h of charging for 3-6 hours usage time. Waterproof design: Designed to be life waterproof, making it durable and ideal for outdoor use. Lightweight: Weighs only 145g, so does not restrict or hinder any movement. Warning light: Get an LED running chest light Adjustable: Adjustable straps with an elastic design to keep your hands free and your body comfortable.