This is my Green Ripley PC, which came from an order back over the summer, with the cover once again being my favorite color! Oddly enough, this one works on my 120 volt Mercury 175w AEL 113...
They're powering green technology lol. (NOT!) To be honest, you really can't tell the PC's voltage judging by the cap color. i mean here they custom ordered the multivolt units gray and the 120V units were ordered brown back before the Grid took over.
I prefer the grey (or even better, silver!) photocontrols or whatever matches the fixture's colour. Some old blue multivolt F-P's here used to fade to a green colour, and the grey F-P's would fade to yellow or even brown.