Apple described it as their "thinnest iPod ever." It is 38% thinner (5.4 mm) than the Nano it replaces (8.78 mm), and adds the ability to use Bluetooth 4.0 wireless headsets, speakers and other devices (such as heart-rate monitors). It still included the Nike+iPod fitness option as well as an FM radio tuner which works when connected to headphones or a stereo jack.