I am a professional Electrician and I have seen a number of 'wonder' drill bits appear over the years. Recently, one of these 25mm x 400mm drill bits enabled me to an hour's work in about fifteen minutes. It was as good as that. Three holes drilled in each floor joist, at 16-inch joist-spacings along the side of a room measuring fifteen feet down one side. That's 36 1-inch holes drilled in fifteen minutes. I remember one model of drill bit, made by CK, that actually drilled more quickly when it had been shattered and developed a jagged-edge as a result. Well, this Irwin drill bit hit a nail and a chunk of metal broke-off one side and it just kept-on drilling as though nothing had happened. There was no point in trying to re-sharpen a bit in that condition, so I just continued using it for another week or two until yesterday, when the sharpened point finally disappeared, and it was all-over for one very tough drill-bit.