Review on FarBoat Vernier Portable Measurement Tool: Precise and Convenient Measuring Solution by Anatoly Yorgason

Aside from being difficult to read (can be repaired with nail polish or black paint, apply and then wipe to keep it in the crevices) there is no indication that the measurement is internal is or the outside diameter is set to zero, which is a problem when the ID doesn't have a zero mark and you're measuring something. The outside diameter has a mark for zero but isn't marked with what it is so overall it's hard to read and confusing to use. I solved the second by engraving an ID marker and engraving what was what.