System 2 kit fan speed is proportional to temperature rise, relieving the system designer of control issues. As equipment warms fans begin to turn at about 1/3 of full speed increasing to 2/3 of full speed if temperature rises further. When the system is turned off fan speed slows as temperature falls shutting off completely just above room temperature. Speed limitation and the use of multiple fans ensure effective cooling with very little noise. The System 2 Kit with 2 fans for most mid-sized cabinets and 2 + 2 kit with 4 fans for the larger cabinet or larger heat load consist of separates, fans, fan guards, drive electronics in a small box, power supply and 2 temperature-sensing thermistors. Both kits are ideal for building into an enclosure at the planning stage. Fans and temperature sensors come with long wires for an easy plug-together and no-soldering installation.