This is a high quality waterproof inspection Deck plate made of UV stabilized plastic. Sleek design hiding the screwholes underneath the top plate. Deck plate tightens by hand twist.
Opening Diameter: 6"
Overall Diameter: 8"
Distance between two opposite screw holes: 7 1/4"
There are a total of 6 holes spread evenly on the rim of the bottom plate.
You will need to use silicone waterproof sealants on each of the six screw holes to prevent water from seeping through the holes.