The suction cups are of very good quality, but the valves are a little problematic. At first, some may not suction properly, but there is a booklet and a video on YT with instructions. However, some may let air in and not hold or stick properly, which cannot be fixed and renders the suction cup useless unless you have additional valves. If the valve mechanism was the usual one (where you pull up the valve and it comes off directly without any room for the suction cup to not stick), then it would be excellent!!
P.S. The case is excellent