TuneBand for iPod nano 4th Generation (Model A1285, No Rear Camera), Premium Armband, Compatible with Nike+iPod, BLACK COMPATIBILITY: Fits a bare iPod nano 4th Generation *only*. It has the following model number on the back: A1285. If you own a different device, then please search Amazon for the appropriate TuneBand. ACCESSIBILITY: Durable silicone skin allows access to all ports and buttons. Enjoy unobstructed access to your music! COMFORT: One (1) soft, elastic Velcro strap accommodates arm circumferences between 11" - 14" (about 28cm to 35cm). See product description regarding longer and shorter straps. CONVENIENCE: Two-piece design means you can use the silicone skin as an everyday case, and then attach the elastic strap when exercising. NIKE+IPOD: Many customers use the TuneBand with the sensor from the Nike+iPod system (sold separately on Amazon). Also search Amazon for "Shoe Pouch for Nike+iPod".