The 134 "jug" I bought (30lb) is NOT standard 1/4 flare. It is some special "new" fitting and required an adapter. The first one I bought off ebay did not fit. I don't know if it was the incorrect fitting, or just threaded wrong by the guy in the backyard shed in China. I don't know if some are different. "It would seem" that 134A would be "standardized" LOL