The Wood Working SOlutions Universal Callipers are Australian designed and made. They are versatile callipers that do a similar job to vernier callipers but on a bigger scale. They can be used to measure spindle diameters, the thickness of bowl walls and even the thickness of timber. I use mine a lot.
See my video review of these: https://www.youtube.com/watch?v=hclKi0_QeLY