It goes through the rubber I don't recall the size of the screw but I have 9 more being shipped I'll let you know then.
There are instructions that tells you what size hole to drill to punch the plastics eat into the wall for the screw the screw is adequate the sheet rock is only 1/2 inch screw is twice that length
The diameter of the base plate for this wall door stop is 2.25in.
This wall doorstop is made of solid brass and should be okay for use outdoors.
Screw is #10 x 1.25 in. flat head wood screw, phillips. Drywall anchor requires a 1/4 in. hole.