Conversiones is a free Android app developed by Apew-Dev.Com, which allows users to convert quantities between hundreds of units. The app includes conversions for length, area, volume, mass, time, speed, energy, fuel consumption, and fractions. It also features a historical reference of outdated units, so users can visualize the units currently being used and the ones that have been phased out.

Overall, Conversiones is a well-designed and useful unit conversion app for those who need to convert quantities frequently. It provides a comprehensive list of units and is easy to use. While the app is currently limited to the aforementioned conversions, the developer promises to add more in future updates.