Best way to seal off a mail slot

Recommended sensor for mail slot? - Get Started mail slot hood Buy Deltana MSH158U19 Solid Brass Mail Slot Hood for Open Back Plates in Matte Black at mail slot on door If you have an open back mail slot but want more privacy, this handsome brass hood will do the trick It's large enough to fit over smaller mail slot trim,

mailbox slot in wall Solid Brass 13 x 3-116 Heavy Duty Mail