The Iphone Victrola is a passive audio amplifier, meaning it is not electrically powered and has no circuitry inside whatever. When an Iphone is placed in the soft leather lined slot, the Iphone speaker lines up with a copper tube that transmits the sound into the trumpet bell. That's a real trumpet by the way, so horn parts on songs sound particularly realistic. The handle on top opens and closes a gate inside that permits additional sound to exit the body of the device downward, creating a more full sound that balances nicely with the bell. You can open or close the tone valve or find a position in between.
The Iphone Victrola is quite sturdy, soldered and bolted together. It is designed for the Iphone 4S, and may not fit the larger, earlier models. The sound is quite pleasing, I have enjoyed discovering songs that sound especially nice coming through the bell. I've made a video of the Victrola in action, you can see it at http://www.youtube.com/watch?v=mITb07tP4hc&list=UUmaiREeyHPhdgHhpcbuHtAw&index=1&feature=plcp