Only drilled two holes with this drill so far. But easily went through 100mm (4 inch) concrete block with my old corded drill. The start was good with very little slip. The finished hole looks smooth. There are a few chips on the back of the hole. The drill looks sharp and has little wear. - Excellent product for holes up to 125mm deep. Comes in a nice storage tube. The only drawback: the overall length limits some possible uses. But longer bits are much more expensive.