How many times have you tried to open the cases, or the small trunk of your GS after descending from a mountain pass without succeeding if not by prising onto the most differing objects? The depression created inside the cases, which is bigger if the latter are not full, de facto prevents lid opening. With the 3 valve set made according to our specifications, you can eliminate the effect of the depression afflicting the original aluminium cases and the small trunk, when you descend from the mountains towards the plain. Our manually-activated valves are equipped with a small lever which, when needed, allows for compensation of the depression: in fact, all you have to do, is act on the small lever of the valve which will allow for the air to enter and, thus, for the lid to open effortlessly. With our valves, impermeableness of the original cases and small trunk is utterly unchanged. Directions: crystal-clear directions, drawn up in Italian, with photos.