Its like the refillable resort mugs, but just a bigger size. To me its worth it b/c I dehydrate easily so I have to be constantly drinking fluids. I normally refill it a lot with sprite and stuff like that. Also it depends on how long ur gonna be at the park. My DH2B and I are normally there for a little over a half a day, and find it to be very valuable. so we think its worth it, and we use one for the both of us.