The tops are made of heavy duty FF3 acrylic to insure maximum visibility and strength. They are designed with angled sides which allows for the tops to stack or “nest” which saves space for storage and transport. Each case has two cam locks instead of one which is typical of the older style cases. The hinging tabs are reinforced with sheet metal clips for maximum strength. On the top of each case is a heavy industrial strength laminate to help eliminate scratches or other damage. The bottoms are made of made of High Impact Polystyrene and are also specially designed for stacking of “nesting”. All cases come with a cloth to protect them during transport and storage.