the S-mount is a desktop or surface mounting kit for the HkB-2x with adjustable rake for best viewing. the rear plate has xlr-3m/F loop-thru and one rJ45 laN connector for connecting to the intercom. optional power methods include Powerline (xlr intercom connection), Power-over-ethernet (rJ45 ethernet intercom connection via third party power source), or Universal ac/Dc power supply. raised sides protect the knobs of the HkB-2x speaker station from impact. mounted speaker stations can be carried face-to-face if needed due to keyed lugs for easy stacking. anti-slip feet help prevent movement when using the S-mount on a desktop. For temporary setup, the screw holes provided on the S-mount allow simple and quick surface mounting.