The Sonos Connect:Amp is the amplified base station product in Sonos's wireless hi-fi line-up. It performs identically to a Sonos Play:5, but--unlike that models built-in speakers--you'll need to add your own speakers to the Connect:Amp.
The Sonos Connect:Amp includes two pairs of speaker binding posts (55W/channel output), a subwoofer output, and an analog stereo input. As with other Sonos products, it can be controlled on an iPhone, iPod Touch, iPad, Android phone, or many Android Tablets (including the Kindle Fire) by downloading a free app.
For more information on how Sonos products work, read the Sonos Play:3 review.