Ftng(perm) Refrig 45 Deg Flare, Straight

The 45 degree flare refers to the flare angle on the fitting end, which is standard for refrigeration-style connections. That flare geometry is what creates the seal when the fitting is tightened against a matching flared tube or component. It's a permanent-style fitting, so once it's assembled it's not meant to be taken apart and reused like a standard compression or threaded connection.