License key works on owned by the same user (unlimited installs, but same user simultaneously? – DiskDigger allows activation on several machines as long as it’s same person/company, but check EULA for concurrent use).
Free/basic edition
Entering a license key removes the "reminder" pop-ups and allows for seamless batch saving of recovered data. DiskDigger for Android
Once you purchase a license, you will receive a diskdigger.key file via email. Installing it is simple: