M5 x 16mm Round Thumb Screw Flat Thumb Head Knurled head provides extra grip for manual tightening. Typically found on thumbscrews, a knurled surface on the head provides a better grip surface, making it easier to manually tighten or loosen fasteners. Thumb screws are designed to be tightened and loosened by hand. Tools for tightening or loosening not necessaryKnurled thumb screws are installed with your fingers and are used to install camera accessories and camera set products.Package Includes:4 x Thumb Screw Adapters with M5