The Williams Sound WIR TX75B infrared transmitter in 3.3/3.8 MHz ensures members in your conference room, courtroom, classroom or even various other mid-sized venues receive direct, crystal clear interaction of your message without sacrificing security. The sleek and even stylish TX75 is designed to maximize coverage area for as much as 5,000 square feet in single-channel mode when using a WIR RX22-4 receiver. 2 slaves (WIR TX75-S) can be added for more coverage to achieve as much as 5,000 square feet each (15,000 sq. ft. total) when mounted as much as one hundred feet from the master transmitter. Placing more slaves within the same room increases coverage and even enhances freedom of movement. A single CAT-5 cable carries both power and signal to slaves making it a truly one-cable connection. Mounting bracket and even international power supply are included making installation simple.