There’s a good reason this was the last pneumatic tee fitting on the rack:
The center fitting should be a male 1/4 inch NPT connection, but it’s completely un-machined. Alas, I no longer have a 1/4 NPT die in my tool chest, so it’s not an easy fix.
The two female connections are fine, so it must have been one of those rare QC escapes.
Lowe’s marked it down to $0.47 on clearance and I still couldn’t justify buying the thing.