We bought 4. The ones that worked are pretty functional. 2 of them, however, were punctured - where the glass is pressed in to trap the bearing, it was actually pressed too far, resulting in a small hole through which air would escape! We had to wrap them in electrical tape to prevent this, which is a blight on the all-glass aesthetic.
KEEP IN MIND: If your hookah's hose ports are at an angle (as they are on many glass hookahs, esp. barrel-bodied designs) instead of straight up and down, the bearing will NOT always sit completely over the hole. Would be nice to see a deeper, narrower funnel that the bearing is more likely to fill at even when tilted (probably max 45 degree angle). No stars off for this though.
The pharaoh valves work perfect, no longer need to keep the finger over the other hose for suction. No change in the pull 10/10 good product