DapSync 1.6.1 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 Audio & Video Tools, more precisely Editors & Converters. We recommend checking the downloaded files with any free antivirus. This Mac app was originally produced by Solocontutti.
From the developer:
DapSync is a simple utility that synchronises your iTunes library with a DAP (digital audio player) or an SD card for the DAP. DapSync supports up to two storage devices and can prefix track filenames with track numbers for DAPs that do not sort on metadata. DapSync saves files on your DAP in a folder hierarchy based on artist and album name.
That's it - DapSync does nothing else and I don't intend it to do anything else.
You may want to check out more Mac applications, such as DapSync Light - App or DapSync Light, which might be related to DapSync.