The Energon Pub

I recently scored a Primus figure on eBay very cheap, but didn't realize until after I paid that there were parts missing. I've tracked down missiles, but I still need the omega lock part, the key, and especially the half dome piece that attaches to the back part, which most people seem to refer to as the "butt flap". If anyone has anything available, I am willing to buy, and have a few items I'd be willing to part with in trade.