Medium Circle Centre Finder

I designed a Mini model workers Circle centre/center finder recently and this is a medium sized circle finder with an addition, when trying to get the dimension of a smaller rounded object say up to 50/60mm with conventional finders I found it difficult to hold the finder and the component together, this model alleviates that issue as it has a raised angle to assist when holding with one hand whilst you mark with the free hand a very useful addition I think, this has the same chamferred slot for