The Sennheiser EK300 IEM-G2 is the bodypack receiver with earphones for the EW300 IEM Wireless Monitor System. With its new battery concept (which can use AA cells or rechargeable batteries) and improved efficiency, the EK300 IEM-G2 receiver has a battery life of up to 10 hours! The bodypack case even includes external charging contacts. The EK300's smaller, more durable metal bodypack resists abuse and makes for easier placement and concealment.