These universal, variable focus magnifying hobby spectacles makes use of the Alvarez principle, allowing a single pair of glasses to offer different magnification levels. It adjusts like a pair of binoculars. 

It's as simple as turning a dial. Turn the left dial to adjust the strength of the left lens; turn the right dial to adjust the strength of the right lens. 

FocusSpecs® offer a power range of +0.5 to +4.5 dioptre.

These glasses provide a perfect solution for people that require different levels of magnification for all types of hobby work.