Do not buy! I loved them. They seemed to have great value and how difficult it is to get the right touch to the point. it looks complicated. I clicked the first almost halfway through the series of 83 holes. Then I started checking the points and most of them are misaligned or incomplete. Don't be fooled, they are not like other center drills.
I got tired of my regular drill bits jiggling while I started to drill holes. In some cases the center punch wasn't accurate enough for the positioning, so that was exactly what I needed. Came in a fancy little reusable plastic box that won't fade or lose them. I mainly use them on aluminum alloys in a basic cross-vise drill press, so I can't comment on how they handle harder materials. Delivery was fast, product arrived quickly.