Excellent screws concrete
I tried some long TX screws which require no pre drill they were awful just destroying the wall and after 3/4 in the screws were rounding. I never thought Id try these they were just in my tool box drilled one in a 6.5mm hole with 7mm drill bit it gripped instantly I was so glad as I spent ages trying to get a boiler bracket on this terrible wall. Will definitely buy again and keep more of these in my tool box