The SL100 is the most recent addition to Sirius satellite radio units. It is billed as a portable unit that can be used int he car (with added car kit) or used as a stand alone device
I purchased the SL100 because of two features. The ability for the radio to be portable and the MP3 player function. The unit can only be used away from a docking station (like a car kit) with special headphones that have an antenna built in. This is not pleasurable due tot he design of the headphone. They are very uncomfortable. The MP3 function is easy to use witht he provided software.
I had many problems with the unit. In fact I had to return my first one and get a second. The unit simply did not work in my car. I have had to call the manufacturer many times and have resigned to not using this particular unit, instead opting for a much less expensive model.
The pros of the unit is its sleek design and "talking voce" that announces to you the channel you select. Besides that, I would not recommend this product for use in your car. I had nothing but problems with it and have given up trying to make it work.