PI-Tape 12-40 mm L.C.:0.05 (plastic)

Wrap the PI tape firmly around the pipe surface.
Align and note the zero mark on the vernier scale.
Observe the main scale reading just before the zero of the vernier scale.
Example: Zero crosses 16 mm on the main scale.
Identify the vernier division that exactly matches with any main scale line.
Example: 5th division coincides.
Calculate the final reading:
5 × 0.05 = 0.25 mm
Add this to the main scale reading:
Final OD = 16 + 0.25 = 16.25 mm