This bottle simply doesn't work. When my rat nudges the ball bearing to take a drink, it stays slightly up the tube instead of coming back down. The result is that the tube is blocked and no more water is released. The only way to get it working again (briefly) is to squeeze the bottle, something which my rats obviously cannot do themselves. I didn't even notice this problem for a whole day meaning my rats had nothing to drink during that time. It's not even worth returning due to the postage cost being around half of the bottle's price.
If you need a bottle for your pets then I would strongly suggest that you try elsewhere. This one is worthless and potentially puts your pets in danger (from thirst). A bottle that leaks would be better than one that provides no water at all...