Our website provides a free download of Mountain Duck 18.104.22.16866. The actual developer of the software is iterate GmbH. The program lies within System Utilities, more precisely HDD Management.
From the developer:
Mountain Duck lets you mount server and cloud storage as a local disk on Windows and Mac. Using this, you can open remote files with any application and work like on a local volume. All major protocols such as FTP, SFTP, WebDAV, Google Drive, Azure, and OpenStack Swift are supported.
You may want to check out more software, such as Auto-Duck in Real Time, Duck-1 VPN or Duck Marines, which might be similar to Mountain Duck.