Blast it or dump it – either way, the competition’s going to get soaked The Nerf Super Soaker SplashMouth water blaster has 2 modes for unleashing water. Battlers can pump to fire a stream of water, or they can open the hatch and fling all the water in one tremendous wave Fill it fast by dunking it in water with the hatch open. The tank holds up to 20 fluid ounces (591 milliliters).