Philips 151167 180-watt T15 SOX180 Low Pressure Sodium HID Light Bulb Philips 180-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 T21 Shape with D.C. Bayonet Base Operating Position: Horizontal +/- 20-Degree