Monoprice 300W Rotary Impedance Matching Speaker Volume Control with Color Kit, Connect Multiple Speaker Pairs to a Single Power Amplifier or Receiver

Allows you to connect multiple speaker pairs to a single power amplifier or receiver. Support amplifiers with up to 300 watts of output power. Fits into standard single-gang low-voltage junction boxes or mounting brackets. It increases (or decreases) the impedance of the connected speaker pair to ensure that the overall impedance level presented to the amplifier is high enough to prevent damage to the amplifier.