This mount allows you to mount a magnetic lens to the Raspberry Pi camera module. These magnetic lenses are sold as sets online for attaching to mobile phones. They are cheap and a great way to alter the standard Pi camera module.
This mount can be screwed to the Pi module using 2mm nylon bolts. An 8mm metal washer can be inserted and the magnetic lens will simply stick to the washer. Depending on the fit the washer can be held in place with a few small drops of superglue.
I combined this item with my "Pi Camera Cylinder Mount" to assemble a security camera.
As this mount doesn't support any weight and isn't subject to any forces the infill doesn't really matter. 10%-20% will be fine. No supports required.