The Mackie Powered Sub-woofer Rental has a built in 600 watt amplifier and 18" woofer with dedicated volume control for the sub unit. The input/output on the sub is XLR. These subs allow for a number of wiring options including high-pass output and full-range output.
The powered sub woofer rental is a great addition to powered speakers. Subs will give a PA system a bit more low-end frequency or perhaps a dj-ing rig the bass it requires. Also the sub rental is great in concert with powered speakers when used for music playback or movie audio.