Suki Grub Screws, also known as Suki Grub Screws have a recessed hexagonal drive port and a cone point Since these screws are headless, they are ideal fasteners to use for security purposes, as they cannot be easily unscrewed These screws can be driven in manually by an Allen wench or mechanically When screwed in, the entire length of a grub screw is encased in the material that it is fastening, which makes it more corrosion-resistant compared to traditional screws It also allows for the screw to be tightened with more torque as the surrounding material reinforces its head in the process The M value is indicates the pitch of the screw thread