I bought these to drill studs for an electrical job (drilling 2 x 4 wood to run wires through) and needed some new bits to replace some of the worn ones I have. I assumed they were cheap but also figured they would last since it was all wood. But that's not the case. The 3/4" bit broke one of the spurs and the blade on one side on the first heavy knot I made and the 1" bit dulled so much from the start that it was unusable. I drilled about 20 holes with 5/8 and 7/8 bits but they aren't sharp enough to make a clean hole. My expectations were low, but I'm pretty sure they aren't made out of tool steel. Yellow coating on the surface is worthless.