It is an integrated monaural subwoofer amplifier/crossover system designed as a low distortion power source for Stealth Acoustics invisible subwoofer panels or other un-powered subwoofers.  The SA255 MKII can also be used for full range speakers when the low pass filter is off.  Intended for whole house audio or home theater bass applications, the SA255 MKII may stack with other components or mount in a standard 19” equipment rack requiring two RU spaces (3-1/2”) with the provided removable rack mount ears. The SA255 MKII delivers a solid 250 watts into an 8? load and 350 watts into 4?.  A variable low pass, 18db per octave filter allows for infinite crossover points from 50Hz to 100Hz.