Recommend for engineers, fabricators, designers, and students who like to try with the slick tape measuring feelings. You can verify the input lengths before performing super fast calculations. It is a great tool especially for aluminum framing fabrication. Two videos show exactly how smooth and how fast the calculations. Features: 1. no more digits input keys. 2. continuous calculating methods. 3. has 6 output formats. (3 for Imperial, and 3 for Metric) 4. has 6 levels accuracy levels. 5. results can be emailed.