Mounting screw size for Video doorbells and solar chargers

What size are the mounting screws for the solar charger and the doorbells? I need to purchase hex nuts to attach the solar charger to thin metal plate/cover which then will attach to the wall.

Hi @user61741. Can you let me know which model of Ring Doorbell you’re looking to install?

I used 6-32 x 3/4" stainless steel machine screws to mount my outdoor solar panel. The stainless steel screws won’t corrode.

Not sure of the metric equivalent.