These unions come in a pair of two and are referred to as 1-½" with threads that actually measure 2-3/8" ID and a slip end tail piece for plumbing thats referred to as 1-½" with an actual ID of 1-7/8". The threads on these unions are not universal, they fit standard pool and hot tub pump threads and pool filters with standard threads referred to as 1-½". They will not fit any any pool or hot tub pumps or pool filters with proprietary threads such as Hayward, Pentair, Jandy Zodiac etc.
Please note
These unions are not compatible with any softsided pools like Bestway and Intex as they have Asian metric sized plumbing.
