Proportional speed thermostatic fan control for DLBX - Proportional speed thermostatic fan control extends both equipment and fan life and reduces service calls by varying the fan speed of up to four fans, based on the temperature within the enclosure. Featuring three temperature ranges, the fan control can be set to activate proportional to the enclosure temperature, or to come on at full power whenever the temperature threshold is reached. Mounts to rackrail brackets or any flat surface, includes two 15 Amp outlets.