Best way to seal off a mail slot

Help & support - Royal Mail Click & Drop mail drop slot If you're sending an item, simply buy postage using Click & Drop, or the Royal Mail App Post Office branch and cannot be dropped off at a Parcel Postbox mailbox slot Since it is a corridor wall, the opening itself needs to be fire rated I'm looking for suggestions Most of the mail slots I find are more

mail slot privacy hood This video is about our Wall Mail Drop