I mounted this mirror on the side of an Ikelite housing for my camcorder. It is definitely much better than using the camera's view finder and a simple solution for being able to view the camera's LCD screen.
The obvious problem since it is a mirror is that you see the mirror image. If you are panning following a fish, you pan in the opposite direction of what appears on the mirror. It takes a bit of getting used to but is worth doing since this is a simple low cost solution accessory.
Installing it is easy and straight forward (Takes 5 minutes) and the adhesive is very strong.