A side: ISO-KF16 / KF16 / NW16 /QF16 flange
B side: 1/2" FNPT tapered thread, follow USA standard
Pipe sizes do not refer to any physical dimensions
A 1/2" NPT pipe thread when you measure it. It is actually 0.84" instead of 1/2"
TPI: 14 TPI | Thread angle 60 degree