Philips 327817 35-watt T15 SOX35 Low Pressure Sodium HID Light Bulb Philips 35-watt SOX T15 Low Pressure Sodium lamps offers high energy efficiency Long Life - Lasts up to 18,000 hours Vibration Resistant - Rough service arc tube support system provides protection against shock and vibration T15 Shape with D.C. Bayonet Base Operating Position: Base Up +/- 110-Degree