Tuneband for iPod nano 4th Generation, Armband Compatible with Nike+iPod System
I bought this for using my iPod Nano 4G while working out.  It works quite well for this purpose.  The iPod slips into and out of the silicone skin pretty easily. The arm band adjusts easily, and holds well.  Accessing the hold switch while the skin is on is difficult though.  Also, I cannot dock the iPod into my speaker/docking station with the skin on.  The instructions that come with this product are virtually useless - I couldn't figure out how to place the plastic protectors, so I just don't use them. 