This 3" screw is used where the lead shield is buried and can't reach it with the regular 1 and 1/2" screw. The head is 1/2" wide.
Comes in a package of 50 for $25.
If you want the screw with a wider head you can find it on our Shutter Screws and Hardware page. (Click: SIDEWALK SCREW)
3 Inch Storm Panel Screw (Pack of 50)
Use #3 phillips screwdriver to install and remove. You will strip the head otherwise.