Fillister Head- Fillister head screws have tall cylindrical sides and a little bit rounded heads. The upper profile can make these heads better match for further slots in comparison to pan or spherical head screws. Zinc Plating: This is amongst the most economical and simplest corrosion security coatings for screws. https://andyjucio.theblogfairy.com/28942879/considerations-to-know-about-types-of-screw-heads-uk