The AirCurve by Griffin is a dock for the iPhone that also amplifies your sounds or music without the use of a speaker or electricity. The dock is made out of clear plastic and feels very sturdy, with the AirCurve you get 2 iPhone dock adapters one for the 2G iPhone and one for the iPhone 3G/S, you cannot use the AirCurve with an iPhone that has a protective case on it. The AirCurve does not really amplify music to a degree where is is very noticeable, i would say there is only about 20% of volume increase using the AirCurve, however it is also a dock for your iPhone and by using you own usb iPhone sync cable you are able to charge and dock your iPhone and get some volume increase. I would not recommend getting the AirCurve only for the sound amply feature because it is not that noticeable. The price is low compared to other iPhone docks. It looks really cool and it works great as an iPhone dock.  Price $19.99.

Thinkgeek.com