Jeweller Dave Wilson of http://www.celticdreams.co.uk/ explains why the most important tool in his workshop is the Optivisor. He also explains the different lens configurations and the additional Loupe. Available in the UK here. https://www.eternaltools.com/optivisor-headband-magnifier
Purchase here https://www.fdjtool.com/tools/magnifiers/headband-magnifiers/optivisors/ Jewelers and crafters alike have found that having magnification to see their work is helpful, but choosing the right Optivisor for the job can be difficult. FDJtool.com gives you a few quick tips to help you make the right decision.