This thing is the perfect size! It is small enough to forget it is attached to your hand and big enough to sporadically hydrate you on hot days. I fill it up 3/4 with water and freeze it. Then fill it up the rest of the way with water. Half way through the run in 90-100 degree heat it has thawed out and refreshingly cold. It shoots the water in your mouth quickly so as to not mess up your breathing. Only downside is that I am not sure the bottle snaps out of the handle. I tried to take the bottle out but I was afraid it would break so i just left it...