In the mid-2000, Wu-Tang Clan lent their name to these old Kung Fu movies. Base on the source (all full screen, all English dubs), I would say they're from old VHS copies. Ground-Zero Entertainment claimed to have remastered the video and audio, claiming the soundtrack to be "remixed" in some cases. Because of the source material, you still see ton of film artifacts and audio sounds like it's from a mono source.
These three movies (Gravedigger, Shaolin King Boxer, and Fury in Shaolin Temple) were previously available as single releases, so it was nice that the boxset was a cheap price of $10, I guess I couldn't pass it up.
They are in slim cases and these are the original/correct titles listed below - according to this forum: