Duno 1.0 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Education Tools, more precisely Science. This free software for Mac OS X is an intellectual property of FrankByte. We recommend checking the downloaded files with any free antivirus.
From the developer:
Easy to use unit conversions for mass, area, length, volume, temperature and angles.
You may want to check out more software for Mac, such as Gee, Arcade Math Blocks or NLVM, which might be similar to Duno.