This is a camera mount for the backside of the Ender 3 for the ELP 720p camera off amazon (link below). It's a 32mm X 32mm camera. ELP makes several variations of their cameras so measure your camera before you print this. This is a very tight fit and WILL require some filing/sanding to make life easier (even on the edge of PCB of the camera). I've had several cameras on the front side of the Ender 3 and this is out of the way and a better view with my dual fan mount setup. You can mount this with factory screws but will require (x2) 3mm x 12mm long screws and nuts.
I general use 100% infill for smaller prints for added strength but that's up to you. I haven't tried anything other that it on this so print your infill at your own discretion. Its a very tight fit so I would recommend 100% so it doesn't break putting it together.