Features & Benefits The nylon rollers in the bottom ensure smooth movement Comes with a touch lock feature for easy locking Multi chambered for extra strength and better thermal conductivity You have an option to add mesh track if needed More opening for better sunlight and natural air Rain track for a free-flow drain system Hurricane bar option to withstand heavy stormsHurricane bar option to withstand heavy storms • Weather and soundproof Available in a variety of design, colours and hardware options