Simplicity does not rule out clever design; in fact, a simpler product almost demands it. Such seems to be the thinking behind the Rockford Fosgate Universal Bluetooth Audio Adapter, a simple device that wirelessly connects a smartphone to your car stereo.
However, it suffers a common pitfall of simplicity in being short on features.
Rockford Fosgate's Bluetooth Adapter is similar to two other devices I've reviewed, the GoGroove SmartMini Aux and the Kinivo BTC450. The device plugs into a car's auxiliary audio port and connects to a phone through Bluetooth. Play music on the phone and you can hear it through the car's stereo.
However, these devices need a power source, so usually include a USB charging cable and 12-volt adapter to plug into a car's power point. The brilliance of Rockford Fosgate's adapter is that the whole thing plugs into the power point, doing away with the need for a separate adapter.
The top end of the device holds a button that lights up in blue, a 1/8-inch audio output port, and a USB port. Plug the whole thing in, then connect the included 1/8-inch audio cable from device to the car's auxiliary audio port. The USB port is a nice addition, letting you charge your phone or other devices. It has nothing to do with the audio output.
It is a compact solution, but its neatness in a car depends largely on where the power point and auxiliary port are located. In some cars, both are at the base of the console, making it easy to plug both in. However, if the power point is midway on the console and the aux port sits on the stereo faceplate, the cable will have to stretch between passenger and driver, and will likely get knocked out of place or interfere with the shifter.