The proprietary HPL (High Performance Lamp) lamp uses a compact filament, which concentrates the most light where it is efficient in an ellipsoidal reflector.[8] At 575 watts, the HPL lamp in a Source Four produces light equivalent to a 1000 watt spotlight using previous technology. This lower amount of energy consumption saves electricity and creates less heat. The HPL lamp also gives the fixture its name. The lamp (light source) has 4 filament strands, hence Source Four. It is also available in 750W (both 120v & 277v), 375W and 550W (277v) versions. HPL lamps are also available in longer life versions that reduce the color temperature from 3250 kelvin to 3050 kelvin to give the lamp a life of around 1500–2000 hours as opposed to the 300-400 hour life of the standard HPL.