The NV-P2100 delivers high efficiency stereo amplification at 200 watts. The amplifier is compact, powerful, and cooler than other amplifiers. High efficiency technology means you'll use less operating power with the NV-P2100 than with other amplifiers. And output relays eliminate external interference and protect speakers from dangerous voltages, unwanted pops, and extraneous noise.

An ampifier is required when additional amplifaication is required for a zone.  This is often the case when additional speakers are required for a large room or an outside area.