With the exception of the water block, tubing, and power cables, the Nautilus 500 is a completely self-contained unit that incorporates a pump, reservoir, fan, fan controller, and radiator into one relatively small enclosure. The main unit is designed to sit on a desk or on top of a system, with the tubing running from the rear of the unit and into the computer.
The Nautilus 500's enclosure is made of a textured, black plastic and has only a few discernable external features. On the front of the unit, there is a small slot to one side that shows the level of liquid in the reservoir. Should you need to add some water, just above the slot is the metal reservoir cap. Simply remove the metal cap using a large flat-head screwdriver or a even a coin, and water can be poured right in. Also visible on the top of the unit is its integrated 120mm fan. The fan, which can operate at two different speeds, pulls air in through the radiator at the bottom of the unit, and exhausts it from the top.
On the rear of the Nautilus 500 is a switch, a four-pronged power connector, and a pair of quick connections for the tubing. The switch is a simple fan controller which makes the unit's fan run at a "high" or "low" speed. Low speed is for silent operation, while high speed is for high performance. Regardless of whether using high or low speed though, the Nautilus 500 is very quiet. The included power cable runs from the four-pronged connector to the notched slot cover plate, which then connects to any available 4-pin accessory connector coming from the system's power supply. There is no power switch on the Nautilus 500. It gets its power directly from the system's PSU and turns on automatically when the system is powered up. There is no need to manually to turn on the pump like there is with some other water cooling kits.