Why should the mouth valve only be emptied with the cap, and why doesn’t it clamp tightly?

Safe buoyancy is one of the most important functions of RESTUBE. Even if the mouth valve cap is accidentally opened or you want to re-inflate the buoy with your mouth in the water, the buoy should not lose any air. Therefore, deflation is only meant to happen with the cap. To do so, the cap must be pressed down into the valve opening. If you stop pressing down, the valve closes again immediately. Do not try to deflate the buoy with your finger or other objects to avoid damaging the valve.