Fewer screws are necessary to cover anything you may encounter on the jobsite.
6 mm, and 6 x 6 in 152 mm, you can cover all possible combinations with only five different lengths of the STR. 5/16-inch x 3-inch STR Torx Star Drive Deck Framing Screws, 10PK Note that the required T-40 tip is included in each pack. The design of the STR is specific to dimensional lumber used in deck structures and pretty much any other framing needs for that matter, which allows maximum assembly strength. By figuring out all the possible assemblies of a structure, using a mix of 2 x 6 in 152 mm, 2 x 8 in 203 mm, 2 x 10 in 254 mm, 4 x 4 in 101.