Welcome Fellow OPT7-ite,
Only headlights require the even beam dispersion effect of the Arc-Glass. Fog lights due to the tight housing, type of reflectors and specific beam purpose do not require the Arc-Glass technology to achieve a perfect application specific beam pattern.
Thank You,
The OPT7 Customer Experience Team
Live Help Available Mon-Fri 9:30am-6:30pm PST @ www.opt-7.com