Double protected

Sure, for diving or in reasonably clean environments, the protective film is not absolutely necessary before the windshield in the protective housing. But even a single grain of sand, or an insect that pops up on the bike at high speed on the lens of GoPro, more damage is aimed at there when cost 12 protectors. From mudslinging, eg mountain biking or Buggy Race I do not want to talk.

The protectors are easy to apply, crystal clear, the picture quality does not affect and quite inexpensive. They certainly do not need more, but it's reassuring to know you have it just in case, here.