A product review on the Irwin tile and glass drills was a pleasure. They go through ceramic tiles like a knife through butter, they take porcelain tiles in their stride and you can se in another video, just how simple they make the frightening task of drilling through glass. An absolute must for any tool bag and about as versatile as any drill bit we have ever used. You can find out more about them, and but them here. http://www.diydoctor.org.uk/DIY-superstore/drill-bits-holesaws/drill-bits-glass-tile-core-diamond/tile-glass-drills/glass-tile-drill-bit-5-piece-set-4-10mm.html