HT Allen Button Head Screw have a rounded, low-profile head with a hexagonal socket instead of a slot or an exterior hexagon that may be turned with a wrench. These characteristics make button head socket cap screws ideal for use in small places.

HT Allen CSK Screws, commonly referred to as a "flat-head screw," lies flush in materials after sinking into a surface. A countersunk head screw contains ridges that twist into a material to produce fastening power, similar to other screws. The head of countersunk screws is flat rather than rounded or semi-rounded.