30mm Diameter The original 'Linen tester'. Although deriving its name from the textile industry it is also suitable for inspecting paper, photographs, printed documents etc. 30mm diameter glass lens. 6x magnification. 38mm (11/2") working distance. 25mm (1") square field. Metric and inch graduations. 1mm and 1/8" divisions. Self-standing to free your hands. Folds flat when not in use. Black powder coated body. Complete with plastic wallet.