Niles VCS100K Indoor Stereo Volume Control White 

The VCS100K (FG01652) is a high power stereo speaker volume control that connects between the speaker-level output of an amplifier, speaker selector, or a Niles distribution hub and a pair of speakers. Premium-quality parts and construction ensure high-fidelity sound with flat frequency response and 100 watts continuous power handling. It is designed for indoor use only.

Great for systems large or small
These in-wall stereo volume controls offer intuitive operation for your multi-room audio system. The high-power, impedance-magnifying design lets you safely connect as many as eight controls and eight pairs of speakers to a typical receiver or amplifier without installing a speaker selector or any other type of protection device.