"The ROAM Adventure Co Pump Tank replaces a gravity-fed hose with a built-in electric pump, so water comes out at up to 50psi instead of whatever pressure a hillside campsite happens to offer. Mounted to a roof rack and wired into a vehicle's cigarette lighter, it delivers that pressure on demand for rinsing gear, washing dishes, or a proper shower after a dusty day. It's available in 8. 5-gallon and 9. 5-gallon capacities, each with its own mounting setup, so cargo space stays clear no matter which size fits the build. What Our Gearhead® Experts Are Saying:""I've used gravity tanks that barely dribble out enough to rinse dust off, but this one actually sprays with enough force to knock mud off boots. Plugging into the cigarette lighter and hearing that pump kick on is the difference between a real shower and a hopeful trickle."""