1/4-20 x 1 Phillips Truss Full Contour Machine Screw Fully Threaded Zinc CNPF while the 5 1/2 refers

while the 5 1/2 refers to the length of the bolt

it features a fine thread pitch of 18 threads per inch

This 5/16-18 x 3 1/2 hex cap screw is made of 18-8 stainless steel

These 10-8 x 2 1/2 inch square drive flat head nibs deck screws are made of 18-8 stainless steel for superior corrosion resistance

The 1/4-20 refers to the diameter and thread pitch of the bolt

1/4-20 x 1 Phillips Truss Full Contour Machine Screw Fully Threaded Zinc CNPF while the 5 1/2 refersThis 1 4 20 x 1 Phillips truss full contour machine screw is made of steel and has a zinc finish. It has a fully threaded body and a Phillips drive. The truss head has a low profile and a rounded top, making it ideal for applications where a flush or countersunk head is desired. The full contour thread provides a strong hold and prevents the screw from loosening over time. This screw is commonly used in a variety of applications, including furniture