A specialist 35W Sodium Low Pressure Lamp from Sylvania featuring a BY22d cap and 1800k colour temperature. This monochromatic SLP discharge lamp offers the highest efficacy available (up to 183 lm/W) for this type of light source. Producing a warm yellow light that radiates light in the most effective part of the visible spectrum it is ideally suited to road lighting applications such as pedestrian crossing lighting for contrast with mercury or fluorescent sources. For maximum light levels with minimum energy costs this lamp also lasts an exceptional 24,000 hours.