Symetrix ARC-EX4E Modular Button Controller for Symetrix DSP Systems (White)The ARC EX4e is identical in form to the ARC SW4e. Couple the ARC EX4e with ARC K1e or ARC SW4e to expand remote control capabilities. The ARC EX4e connot be used standalone nor can it be combined with an ARC 2e. Up to four ARC EX4e be combined with an ARC K1e and up to three ARC EX4e may be combined with an ARC SW4e. The ARC EX4e is furnished with a splash resistant overlay and mounts into a Decora faceplate (sold separately) alongside its Modular