Mr.SHOT ABS Plastic Prime Instant Running Water Heater with on/Off Switch Inlet and Outlet Thread Model/Manual (Orange) Mr. Shot prime instant water heater is a novel device made to supply hot water instantaneously. Comparing to other storage geysers, mr. Shot conserves electricity, it is the most advanced heater and as such can be installed anywhere, the specialty of this heater is that it heats only the amount of water needed for the use.