Ruler

★★★★★ Ruler Excellent, Portable instrument to measure the distance parameter

★★★★★ It's simple for impromptu situations at work, which makes it great.

★★★★★ I needed to make a relatively precise measurement to replace a section of vinyl tubing in an emergency without any tools or instrumentation. Downloaded and immediately calibrated via my driver's license (CR80 card standard). Was able to get the ID and OD of the tubing in seconds. I don't think I could've retrieved a ruler from my toolbox or desk drawer at home as fast. Short of having a wallet, keychain, multi-tool, or tattooed ruler this is the best pocket ruler option or if you're in a bind.

★★★★★ Cool app. Get a quick idea of dimensions. Useful when you are buying a product like wristwatch and want to get a quick estimate of size.

★★☆☆☆ It's a picture of a ruler. It looks like it has advanced features, but when you touch those symbols it goes directly to virus-like unclosable ads. Garbage.

★★☆☆☆ Could not use the app because of too many vendors and I do not give my details online just because you've created something that you have to agree or spend 300 hours digging through all the thousands of vendors to uncheck each one of them, so uninstall.

★★☆☆☆ The default scale is way off (40%+ error). Yes there is a calibration setting, but if I don't have another ruler how can I do calibration? It's a flashlight that only works if there is another light source.