The Philips MASTER GreenPower SON-T PIA HPS Bulb is a top-quality light bulb, which delivers a high lumens output. Its a full spectrum lamp made for use during the vegetative and blooming phases. The high-pressure sodium lamp features a clear tubular bulb and its made of reliable and resistant materials. Growers use the high-pressure sodium bulb to ensure healthy and strong crop development. General Information The Philips MASTER GreenPower SON-T PIA HPS Bulb is a high-performance light bulb; The bulb is made for the vegetative and blooming phases; It delivers a high lumens output; Its a full-spectrum bulb.