ONE DUAL MUFF HEADSET, THREE SINGLE MUFF HEADSETS, ONE MASTER BELT PACK (BP-500M), THREE REMOTE BELT PACKS (BP-500R1, R2, & R3), AND ONE GANG CHARGER IN A STURDY CARDBOARD CARRYING CASE. The ProLink 500 is a digital wireless intercom system that allows for full duplex communication between four users simultaneously with the option of unlimited listen only belt packs. The transmitter and receiver operate using the FCC license free 902-928MHs range without the need for a base station. An enhanced version of the ProLink, the ProLink 500 has the capability of transmitting 500 feet line of sight and the ability to communicate through glass and walls. It also has Bluetooth capabilities.