1/4-20 x 2 1/2 Phillips Flat Thread Cutting Screw Type F Fully Threaded Zinc MTP188 which means that it has

which means that it has a sharp point that cuts its own threads into the material it is being screwed into

The 4-40 x 1/2 Phillips Full Contour Truss Machine Screw Fully Threaded Black Zinc is a versatile screw designed for use in a wide range of applications

They feature a Phillips indent drive

6-20 x 3/8 Square Pan Self Tapping Screw Type B Fully Threaded Zinc:

1/4-20 x 2 1/2 Phillips Flat Thread Cutting Screw Type F Fully Threaded Zinc MTP188 which means that it hasThis 1 4 20 x 2 1 2 Phillips flat thread cutting screw is a type F fully threaded zinc plated screw. It has a diameter of 1 4 inch and a length of 2 1 2 inches. The screw has a Phillips drive and a flat head. The thread cutting design allows the screw to create its own threads as it is driven into a material. The zinc plating provides corrosion resistance. This screw is commonly used in a variety of applications, including metalworking, woodworking,