Review on SPAX Stainless Steel Double Thread Fasteners and Screws by Mark Adams

I confess I pre-drilled. Spax screws also worked without pre-drilling. The included bit is pretty good too. Be careful not to rip your head off. Too hard material, too much torque, cheap bits, soft hands, etc. can cause you to rip them off. So if you've never used this type of screw before, spend a few grand practicing trimming. But for sixteen bucks, these are pretty good screws. Yes, and as mentioned before, check the prices before you buy. Sometimes the prices shown correspond to the tables. PS: They are made in USA or Germany (it's a bit confusing with the "OR" printed on the packaging, but better than the usual "Made in China" or "Made to Specifications in China" label).