This NADY ALD-800 RF Listening Assistance System Receiver has been tested and is in working order. It is a wireless headset designed for live performances and comes with built-in headphone jack. The headset is suitable for use by musicians, public speakers, and anyone who needs to hear clearly in a crowd. The diaphragm size is small, and the transducer type is dynamic. The brand is Nady, and the model number is ALD-800. This product falls under the Musical Instruments & Gear, Pro Audio Equipment, Microphones & Wireless Systems category.