The SPAX typical drive T-STAR plus is a so-called internal hexagon. This shape increases the contact surface of our T-STAR plus, allowing the T-STAR plus bits to fit perfectly in the screw head. The optimal power transfer from the screwdriver to the screw through T-STAR plus enables quick work, significantly more efficiently than with any other drive. The countersunk head (also known as flat countersunk head) mills a recess into the wood with its polygonal underside ("pockets") and can therefore be sunk without additional countersinking of the screw hole. The countersunk head sits flush with the surface. Unlike partial threads, the full thread extends over the entire length of the screw. The more thread turns a screw has, the greater the tensile and compressive forces that can be transferred from the screw to the wood. Our full-thread screws are primarily used for highly stressed wood connections. The term 4CUT refers to the square shape of the screw tip. These edges displace the wood fibers during insertion and create space for the screw's core diameter. This reduces the spreading pressure exerted by the core in the wood and prevents the wood from splitting near the edges. The necessary torque of the cordless screwdriver is also reduced, as the screw's core does not have to "squeeze" into the wood. With WIROX, SPAX has developed a coating that is far superior to galvanization in terms of corrosion protection. WIROX does not use chromium (VI), and the screws remain just as load-bearing and environmentally friendly even after years in non-directly weathered outdoor areas. WIROX screws are the first choice for all open structures without direct weather exposure, such as carports or pergolas; for direct weather exposure, such as on terraces, we recommend our screws in stainless steel.