The Carson OD-75 1.5x TYMate Magnifier attaches to any brimmed cap to provide hands free viewing. Whether you're outdoor tying fishing flies or building model boats and planes, this 1.5x magnifier will help you see small details. The acrylic lens is distortion-free. The LED lights will come in handy in low light and also help you see those small items and details needed to complete the job. The magnifier folds into its own built-in case. It operates on three GP395 button cells.