This purchase was necessary for my husband's work where he will be measuring light on various objects. In order to get to know the product, it was of course important to unpack and test it. He felt the instructions could have been more informative. After inserting the supplied battery, he quickly found the device easy to use. To test the device, he used it in and around our home to get different readings in different areas. He said it works fine. It measures light from very faint to very bright. It will measure any light. The device is not heavy, so it is easy to carry. Another handy feature is the built-in memory. It has a large display that is easy to read. Best of all: It works! This completes the required work. The device also comes with a carrying case so it is easy to store away when not in use.