Kreg Pocket Hole Screws- All of their screws utilize a #2 square drive recess. The deep recess of the square drive provides positive driver engagement to reduce cam-out.
Like every KREG product, their screws are manufactured from the highest quality materials. To manufacture a virtually unbreakable screw, industrial quality steel is first case-hardened and then coated with a dri-lube finish which reduces driving torque and gives them their bronze appearance.
The pan head (SPS) is slightly smaller in both head and shank diameter than the washer head screw and is a good alternative to the washer head screw if both mating workpieces are made of extremely hard woods. The pan head style is also of benefit in the 1" length as it allows one to join 1/2" stock and easily seat the screw head below flush.