Ultra super problematic 7/16"-20UNF connector, I had to flip the whole internet to find an adapter on Ebay to 1/4" BSP so I can connect whatever I want to it, this adapter costs 18$, the seller is called "context-pneumatic-supplies-cpm" on Ebay if anyone wants to buy this adapter too. I advice to put blue threadlocker/threadsealer (242/243) on the connections to seal them good (the seal is not permanent, you can open it), you need to wait 1 day before turning on the pump after you put threadlocker, so the pump will not suck the "glue". Also it is better to buy a full synthetic oil like "VacOil Elite Z" with good vapour value for maximal possible vacuum in this pump, good luck.
Spend the money. But if you don't, this is close. Super.
Everyday, it's an easy deal. Good working with you.