The iSkin Duo's inner layer gives the iPod light weight protection with added side shock absorbers and click-wheel protection. It can be used alone when using Apple's lanyard ear buds or other third-party accessories that connect to the bottom of the iPod nano. For maximum protection, combine with the Duo's outer layer . By adding the stylishly cool outer layer, you can give your iPod nano the ultimate in protection and functionality with the addition of an ultra-clear screen protector, rotary beltclip and click-wheel cover.