This Mailbox is for:
Barzilai only
It's only for:
"18A Frederick Rd." or "18 Frederick Rd, Apt A"
Which is for the upstairs (this is not a shared mailbox)
(Or if sender forgets the "A" but it's for "Barzilai" then please do deliver it into this mailbox..)

Mailbox is not for Mail to "Ed Gills" or others at "18 Frederick Rd" (without the apartment "A")

Without the "A" it is for folks downstairs; they do not have any mailbox here, because they are a financial company and want extra security, so they use a P.O. Box - right at the Thurmont post office! They have no USPS mailbox here.

Why it's not "18A" and "18B" but instead is "18" and "18A" I don't know, the convention is the one given at, and also given over the phone by Thurmont USPS several months ago; not one we created, so while somewhat confusing, we appreciate your correct delivery: Anything for "Barzilai" and/or with an "A" for Apartment A, does go into this mailbox (only resident: Harel Barzilai) Anything for "Ed Gills" goes to their Thurmont P.O. Box number (that is sensitive financial info and they appreciate not having that mail in my mailbox..)

I am a long-time supporter of USPS (letters, petitions). I only wrote on the envelopes because the carrier(s) clearly were not aware, and that was standard practice in Salisbury MD where dozens of times people at apt complex hand-wrote "Not at this address" on mis-delivered envelopes. It is to be helpful and get the carrier's notice to correct the records. Thanks for understanding and for delivering "through rain or snow or gloom of night". (I will put copy of top of this letter so substitute/alternate postal carriers are made aware too) Thanks again.