Hi Boyan, i knew i had seen these bits somewhere before, i have purchased quite a few bits off Drillman but didn't think to check this time. I will certainly be buying a few of them for tapping, but they are of no use for the current task as the depth is only .20 inches and i need to be able to get down about 15 mm ideally for the current job, but thanks anyway as i will need some of those drillman bits at some point