This auction is for a lot of 9 Eaton Fittings. These items are 45 degree. One end is smooth, there are no threads, flange, or flares. The other end is threaded with a recessed rim for installation of a seal.

The protective cap by Alliance Plastics has an indicator size TS 21. Based on this information the threads may be standard or metric roughly 1 11/16 inch.

I can not verify this after research, it is still only a guess. It appears to be 45 degree Braze to ORS with 1 11/16 pipe threads, possibly stainless steel.