Apex triple square screwdriver bits. Triple square bits, also known as XZN bits, are a type of screw drive with 12 equally spaced tips, each with a 90° angle. Its name derives from overlaying 3 equal squares to form such a pattern with 12 right-angled tips. Quality design and construction give Apex Triple Square screwdriver bits a long service life and durability. With Apex Triple Square screwdriver bits you are assured of high quality and industrial strength.