The 3-megajoule, 35-kilogram module stores all that excess heat by melting a waxy phase-change material augmented by a variety of other thermal materials. What exactly these materials are seems to be a trade secret at this point, but by allowing that heat energy to be consumed by melting that waxy substance, the device can pull 230 kilowatts of heat away from the primary weapon. "To put it into perspective, it's the equivalent of melting about 20 pounds of ice in 13 seconds," said Dr. Paul Clark, a manager in Advanced Power Systems at General Atomics, in a press release.