Here's a pic of the ballast door. It's pretty cool how you just unplug the ballast and the ground wire and that's it. No wires to cut or splice together.
it doubles as the ignitor base and the male half of the powr/door plug. The plugs on HPS and Mh lights are identical so you can use any wattage M-250A2 powr/door on any M-250A2 fixture.
Is that what that is? I thought it was just a plug/disconnect for the powr/door?