In support of the new 13" MacBook Air Retina USB-C launch, we are pleased to offer you the option to purchase an updated insert for your BookArc. This means that if you want to use your new MacBook in closed-clamshell mode and already own our most recent BookArc, you can simply add the updated silicone insert (insert E) for the perfect fit. Please check the compatiblity chart before purchasing to make sure you have the correct BookArc (inserts are only availble for our most recent BookArc version and will not fit models pre 2015)