Based on my observations this product was not WHAT I expected.It claimed to be diamond-tipped and suitable for glass drilling, but it failed to deliver. The only pro was that it arrived quickly, but it wasn't enough to make up for the cons. The drill was tricky to use and didn`t make clean cuts, despite being marketed as an industrial and scientific tool. i wouldn't recommend this to anyone in need of precise cutting tools..
Pros
Diamond tipped for precision drilling on glass surfaces.
Cons
May shatter or crack fragile glass surfaces during drilling.
These bits work great and are a lot cheaper than other diamond bits available at your local hardware store. When drilling in hard rock, you need to use the drill bit properly so as not to damage the drill bit. Keep your speed low and use the water to cool things down. If you drill hard and fast, the metal melts.