These lenses are excellent. Yes they replace the one you've damaged which is what they're meant to do, but before I'd thought about getting replacements I think I was a bit precious about the front lens as I always am with optical equipment. Well not now! Now I don't care if i scratch the lens because it's so easy to replace! So i'm much rougher with the GoPro than I used to be.
Lenses are dead easy to replace as you get the correct screwdriver in the kit. Awesome.
Buying these replacement lenses for the GoPro case, has given me the confidence to use the camera in very extreme cases knowing that I can replace the lens should it be scratched or damaged, I bought them without the need for them, and still haven't used them but they are there if needed without the possibility of ruining a whole film shoot. A great spare to carry around.
The lens is good quality. I did find the screw driver pretty useless as the handle twists as you try to undo the screws, binned the screw driver and used one with a good handle. Seals are 100% waterproof, test it out by going Kitesurfing in Gale force winds and 8 ft waves, no leaks.
The fact it comes with the screwdriver needed to change the lens is a massive plus as I had the lens changed on my Gopro case within 5 minutes of the postman delivering the kit. Then put the spare lens, screws and little screwdiver in my camera bag for any future accidents.
You will at some time need this and it's simple to replace the lenses, I scratched and replaced lens after Gopro handlebar mount broke with the vibration, this item is cheaper to buy on Amazon than the Gopro site