I am specifically looking for a bung for a coolant bottle factory Degas style cap as shown in that pic. I've gone through the listings at Atech and even emailed my rep to see if they've got a listing for it. I am so surprised that these aren't all over the market since they've been using these caps for over a decade now.
I may have to call Canton directly to see if they would sell me a couple..... or get my CAD guy to draw one up and I can start selling them!!