Sadly, this didn't work for my very large dog. I think the ball and aperture were just too small. Still think it's a great idea - though maybe more for small animals.
Bought this for my puppy as he likes drinking from taps ! Found the top a bit fiddly at first but then got the hang of it and the puppy loves it ! You need to hold the bottle at the correct angle so it doesn't come out too quickly but water isn't wasted generally. The container is strong and designs are stylish. Not that the puppy minds but makes me feel good when people ask where I've bought it !
Very practical, of course, but the best bit is watching our two dogs competing to lick the bottle. Excellent entertainment. What you might call a tongue tangle!