An ad bar appears across the ruler at the bottom of the screen. Its in the one worst place it could possibly be to prevent being able to measure an object. Its only a buck to remove them, or is it? They play a game with "how much is it worth to you to remove the ads?" The polices range from $0.99 to several dollars. Its just a measuring stick. Businesses give them away for free. Its not worth a buck to me. Time to find a new app.
Rain on Sunday about Ruler for iPad and iPhone, v3.0.1