Making a device waterproof means protecting the electronics inside against contact with liquid of any kind. However, if a device uses air cooling, it seems impossible to also make it waterproof without the unit overheating. However, Fujitsu has managed to overcome such a limitation through design.The company’s new Arrows Tab QH77/M is a 2-in1 tablet that works with or without a keyboard attached. It is also waterproof, but instead of running a fanless ARM solution, the Windows 8.1 tablet uses a Haswell Core i5-4200U processor (a Core i7 chip is also an option) and cooling fan to pump heat away from the chip.So how do you waterproof a tablet that requires a fan to spin so as not to overheat? Fujitsu split the internals of the Arrows Tab into two compartments. The delicate electronics including the processor are contained within a sealed compartment that water cannot enter, where as the cooling fan and heatsink are in a compartment that can flood with water if submerged.The two areas are linked by a heatpipe allowing heat transfer away from the processor in either situation. When submerged, the heat is dissipated by the water flooding the cooling compartment and flowing over the heatsink. When not submerged, the fan alone can spin to pump the heat away from the heatsink and out of the tablet. So, unless you submerge the Arrows Tab in hot water it should continue to function as normal.The QH77/M complies with both the IPX5/7/8 waterproof standard and IP5X dustproof standard, so should be of interest to anyone who needs to use a Windows tablet outdoors or in an industrial setting. As for features, it pairs that Core i5 processor with 4GB of RAM, a 128GB SSD, and a 12.5-inch 1920 x 1080 touchscreen display. The battery capacity is 46Wh, which Fujitsu claims will give you 16 hours of use between charges. It can also achieve an 80% capacity charge in just one hour.