Philips Lighting 400 W Clear Tubular SON-T Sodium Lamp, GES/E40, 2000K, 48mm

Very good efficiency, low colour rendering, typically Ra20 - 39
Twin Arc versions greatly extend lamp life and allow for hot re-strike after power failure
SON-T Plus offers 20% greater lumen output and longer lamp life

Discharge SON Lamps

These lamps combine high efficiency and long life with an improvement in colour appearance and rendering compared with low pressure lamps. SON lamps emit a golden-white light. The SON-T lamp, with its clear tubular outer envelope, lends itself to applications that demand precise optical control, e.g. floodlighting. The SON-E lamp, with its elliptical glass bulb, inside which a white diffusing coating is applied, suits other applications where such accuracy of light control is not so essential. An ignitor (internal or external) is used to supply the high voltage necessary for lamp strike up. Reliable strike up (when hot, less than 60 seconds) thus is ensured, and a simple choke is used to stop excessive voltage rise. The run-up time can be up to 6 minutes when cold.