The product is 5/16x6 Perc Drill Bit. Easy to use. The product is manufactured in China. ROCK CARBIDE tip maximizes carbide surface contact for longer bit life. Four flute design cleans debris out for fast, efficient drilling. Three flats on shank eliminate bit slipping in chuck.
Not cracked or broken. I stopped every minute or so and let it cool down. I didn't want to break it and had to run for a new drill bit for only 8-10 holes in concrete.
Pros
CARBIDE bit provides maximum contact between carbide and surface for longer bit life.
Incredible product. Chewed my concrete pavement like butter. The smaller part, part of the larger set, worked forever and finally broke. You can't ask for more from this beat.
I have bought 4 of these to drill holes in my 40+ years. old basement, make a cesspool. I was able to drill about 15-20 holes with a drill - 5/16 inch by spraying water. It was enough to break up the concrete. Good price around two and a half dollars.
Pros
Three flats on the shank prevent the drill bit from slipping in the chuck