Carson's lt-30 is a linen tester with 5x magnification and a 30mm lens. a linen tester, also known as a standing loupe, is a useful tool for studying the small details. after use, you can fold the magnifier back completely. The magnifier's housing has a measurement scale engraved on it. this can be read in both millimeters and inches. the scale division runs in millimeters from 0 to 25 mm and in inches from 0 to 1. this allows you to determine the size of an object. Application carson lt-30 This linen tester is a suitable accessory for, for example, assessing fabrics, viewing stamps or checking colors. however, you can also place small insects under the magnifying glass and determine its dimensions.