The EDGE 12 Twin Active Subwoofer Enclosure is an all in one box solution with an integrated active amplifier. The Edge 12 is a Twin Active Bass reflex subwoofer with an exceptional bass response. Active subwoofer enclosure with integrated amplifier all in one box.Ported bass enclosure increases the amount of bass your woofer produces without adding any additional power to your system. Low level input for ease of use with RCA leads and High level speaker input. Low pass filter limits the amount of high frequency output. Product is used, a few marks and some dust (hence price) but otherwise Subwoofer is in full working order.