When installing building elements such as door or window frames in openings, the use of dowels is extremely impractical and time-consuming. Our SPAX RA with full thread and cylinder head solves this problem. It is screwed through plastic and aluminum profiles into pre-drilled holes in masonry or concrete, securely holding all frames in place. For the 7.5 mm thick screws, you should choose a drill diameter of 6 mm, and the drilling depth is the sum of the screw-in depth plus an additional 10 mm. This means for you: you save time with dowelless installation, and the frames hold firmly.