The SPAX typical drive T-STAR plus is a so-called internal hexagon. This shape increases the contact area of our T-STAR plus, allowing the T-STAR plus bits to fit perfectly in the screw head. The optimal power transfer from the driver to the screw through T-STAR plus enables quick work, significantly more efficient than with any other drives. Unlike partial threads, the full thread extends along 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 high-load wood connections.