This K&F CONCEPT wide-angle lens is designed for the DJI Osmo Action 5 Pro and it comes in a thick, heavily built protective rubber casing which should be impervious to most of the things that happen to gadgets inside camera bags.Opening up the case reveals the lens itself which simply screws on the front of the camera when you take off the lens protector that the camera comes with - just take care not to cross the threads as you start to screw it on.The lens is a compound lens that reduces the focal length of the Action 5 Pro's lens to have a field of view which, at the diagonals, extends beyond the magic 180 degrees - you can see this in the photograph of the floor which, if you look at the top left and the bottom right, you will notice that you can see up the walls to some extent. Note that the lens was just a few millimetres away from the floor when this was taken.The lenses themselves are coated in order to reduce internal reflections which works quite well. The only problem that I found with this was really a result of the wide angle of the field of view insofar that if you are not careful when holding it in your hand, you will get your fingers in the shot.This is an excellent fisheye lens converter that takes your action camera beyond the magical 180 degrees and when not in use, it is well protected - just remember to keep your fingers out of shot.