This adapter will only fit select models of Robinair vacuum pumps and nothing else. It has a 1/4 male thread inlet already used in pumps old and new. It also has a 1/2 Acme inlet to connect a 134a Acme vacuum hose to a vacuum pump. Each inlet comes with a plastic cap, and the larger, flared end is what actually attaches to your vacuum pump. I'm giving the seller 3 stars for a poor description and not rating the item as it turned out to be something I don't need and a waste of money which I've heard is still in high demand as this one damn thing "coin" means " was invented by our Roman ancestors (I tinkkk).
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