The MA3501t is a high-output, low-voltage mono power amplifier engineered for use in distributed sound applications. Designed for use with SoundTube and other high-fidelity speakers, the MA3501t provides 350 watts of output power into 4 ohms, 25V, 70V and 100V and 225 watts into 8 ohms. A 12V trigger is provided along with automatic music sensing for remote on/off functions. No controls are available via the front panel; this deters unauthorized tampering with levels or other settings. 2 standard RU size- 3.5? or 3.75? With Feet H X 19? W X 13.75? D. Rugged aluminum housing. UL 60065 Listed