This is not optional
If you are going to buy the hat, get this.  Practically speaking, it really isn't an option.  It is sold separately in order to reduce the price-point.  However, the leash that the cord creates as it becomes increasing twisted makes it unexpectedly difficult to keep up use every other day.  Going cordless solves this.  If you are going to throw down enough money to get the iRestore, then suck it up and spend a few more bucks, do it right, and get the battery back.
Rating: 5 stars