7 Piece Diamond Drill Bits Set, Core Drill Bits for Hard Materials - Tiles Ceramics Glass Stones – Built in Coolant, Fast Dry Drilling - Sizes 3/16" 1/4" 5/16" 3/8" 1/2" - Round Shank, Storage Case

Was excellent to use on the wood, not only concrete. Perfectly makes groove for the cable in the concrete wall. Small visible wearing, another 70% left to use after about four hours of usage on concrete.

Works good, cheap too

I used these on porcelain tiles. They worked very well, and retained sharp after a dozen holes. However, if you happen to get a piece of material stuck inside the hole, it's very difficult to remove. Some competing bits have a slot where you can insert a paper clip to push a trapped piece out. This model does not have a slot. If you get anything stuck, you'll have to grab it with pliers from the front.

Love these for drilling plates for tiered trays!

These come filled with wax for cooling but that makes it nearly impossible to clear the plug after you drill a hole. I dug it out so I could punch the plug out with an awl. Used water (wet rag) to cool the bit. Several holes and they seem to be holding up. Can't beat the price.

The price was good

As advertised

I used this tool in the bathroom shower on some tile that I needed to put some holes in for screws. You must wok slow with this, it got the job done.