The Nady SPA-850 850 Watt Stereo Powered Amplifier is built to last with all the safety and reliability features you"ve come to know from Nady. The continuously variable speed fan will keep the unit cooled with back-to-front air flow. Full operating features include: user-defeatable clip limiter, switchable 30 Hz low cut filter, balanced XLR and 1/4 inch TRS inputs, detent volume controls, stereo (dual-channel, parallel input or bridged mono operating models) with selector switch, binding post and Neutrik Speakon outputs, and ground-lift switch. The advanced safety and reliability features include: soft-start turn on, noise-free on/off, built-in DC offset, independent DC and thermal overload protection on each channel, short circuit and speaker protection, DC servo operation and built-in current limiter. Parallel outputs allow "daisy-chaining" amplifiers, ~115V (60 Hz) / ~230V (50 Hz) AC select switch, clip and signal LED indicators for each channel and the durable double rack form factor with steel casing will ensure your unit is protected.