Retains 100% of lumen output through its 4000 hour life; Dichronic reflector provides intensified crisp bright white light of 700 footcandles - the equivalent of 150 watt while consuming only 20 watts of energy; Annual energy cost is just $4.80 for 20 watt compared to $24.00 for standard 100 watt lamp. (Based on 12¢/KWH - 8 hrs daily - 2000 hrs annually); Ruggedly built; Epoxy coated durable all metal construction; Brilliant white light delivered exactly where needed; Safe 12V transformer integrated in base