Round post cap to suit:
80NB pipe
or
88.9mm Outer Diameter pipe
20NB pipe
26.9mm Outer Diameter pipe
25NB pipe
33.7mm Outer Diameter pipe
32NB pipe
42.4mm Outer Diameter pipe
40NB pipe
48.3mm Outer Diameter pipe
50NB pipe
60.3mm Outer Diameter pipe
65NB pipe
76.1mm Outer Diameter pipe
90NB pipe
101.6mm Outer Diameter pipe
100NB pipe
114.3mm Outer Diameter pipe