Does a regent sodium light have a Mogul Base or a medium base (standard or large s***w in size)?

Question

This one here

http://www.regentlighting.com/common/brands.cfm?pg=Detail&brand=Regent&category=Dusk%20to%20Dawn%3A%20%20High%20Presure%20Sodium&id=12103

Trying to find which replacment bulb to order. The book does not say the base size.

http://www.1000bulbs.com/150-Watt-HPS/

Answer 1

Right in the ad it states "replacement bulb S55", which is a mogul-base.  Sodium lights up to 100 watts are regular base, over 100 are mogul.

http://www.grainger.com/Grainger/wwg/pro...