I am a Chartered Engineer and Heating, Plumbing and Gas Consultant, and I bought the Stanley Intelli Laser to accurately measure buildings so that I can calculate heat loss etc. The device is small enough for the pocket, very accurate, easy to use and easy to read. If you haven't used one of these devices before you may find it a bit fiddly, but the best way is to steady it against a wall or other object to stabilise whilst it reads the dimension. Great piece of kit as expected from Stanley.