Mega fun children's birthday

We bought 8 as guest gifts for a child's birthday. The were then also taken the same at a mega-water battle in Operation. The whole thing is now almost 1 year ago and the 2 remaining in our water pistols are still functional.
Function does the gun as follows:
Screw on the cover of the tank (below the handle) and fill with water. (We take the water from the rain barrel)
Lid screw it and then are set to go:
Push the orange handle under the barrel to the front and the back pulling the water is sprayed ... that has even hammer out our 2-year after a short time: o)