BGTEC Dry Diamond Drill Bits 5pcs 1/4" with Quick Change Hex Shank for Granite Marble Porcelain Tile Ceramic

I used these bits to drill holes in some very hard granite rocks with an electric had drill. The bits seem very durable and after considerable effort and time I was able to drill the holes I wanted. Drilling is slow it takes time. The bits showed up ahead of the predicted shipping time and were packaged in individual plastic tubes. No complaints this product is as advertised.

Decent bit. Worked well to drill through porcelain tile. Four to six holes is about it’s limit. Make sure to use a powerful drill. Good value.