The laser cap comes in solid protective case. It is a one size product as the dome is not adjustable and would not fit fully around larger head/hat sizes. Fortunately my size on the small side of 'medium' and so the cap provides adequate coverage. It is comfortable and easy to wear, with a useful built in timer.
The power comes via a transformer built into a Uk mains plug with a 120cm low voltage cable which plugs into a rechargeable battery pack. The battery pack has its own cable connection into the cap itself. When the battery is charged and connected to the cap, it allows you to move away from the mains when you are using it. The fully charged battery is adequate for about four treatments.
One major NEGATIVE feature is that you are instructed to unplug the battery cable from cap after every use. This cable is hardwired into the battery pack and has an unusual 4 pin connector with flimsly-looking thin pins which plug into a socket hardwired into the cap. When this 4 pin plug /socket connection fails the cap could be unusable without a professional electronic repair; doing so would invalidate the guarantee