SOX Sodium, LPS or low pressure sodium lamp warming up. The lamp gradually turns from red to orange as the neon discharge warms the sodium metal up Stock Photo - Alamy
Philips SOX 35W Low Pressure Sodium Lamp with Box Made in UK | eBay
Philips XWC 121 40 KP zwart met SOX-E 18W lamp met schemerschakelaar Be
Lighting-Gallery.net - North American bulbs, fixtures, and control gear/35w SOX low pressure sodium lamp running on 35 watt magnetic metal halide ballast
LED SOX Lamps | Light Efficient Design 100W LED SOX Lamp Replacement, LED-8104 | 100W, 2200K or 4000K, B22d Bayonet Base