This Theater Solutions weatherproof impedance matching dial volume control is a full range volume control that can be adjusted to meet the requirements of your installation. With a simple change of the placement of two shorting bars on the printed circuit board, you can safely connect up to 8 pairs of 8Ohm speakers to a single amplifier, Receiver or selector box running at 8Ohm. Refer to the charts provided in the included installation manual to determine how to set the shorting bars to ensure the proper impedance matches the level being produced from your amplifier, Receiver or selector box. This dial volume control can be used with any combination of 4Ohm, 8Ohm or 16Ohm speakers by adjusting the shorting bars to the appropriate terminal setting. The dial has 12 steps of attenuation: first position is "off", steps 2 through 7 at 3dB each, steps 8 through 11 at 6dB each and the final position allows the signal from the amplifier, Receiver or selector box to pass through completely. The volume control is completely protected in the weatherproof PVC housing. The housing has a 1" Mount on the bottom for attaching a 1" Pvc wire pipe.