ThisALB-9000 Beltpack ReceiverfromAnchor Audiooperates in frequencies between 902 and 928 MHz. It is designed to accept audio transmissions from products such as the Anchor Audio Liberty, Go Getter, and MegaVox PA systems. This beltpack is also integral in many products such as the AL-900 4-User Assistive Listening System. Designed to facilitate clearer audio for the hard-of-hearing during museum tours, lectures, or other single-focus events, this unit can receive audio from up to 500' feet away. It sports a volume adjuster.