The master key, also known as an arrow key, is specific to a mail carrier's route and a geographical area. ... The keys can open up the postal service's signature blue collection boxes, the mailbox panels at apartment and condo buildings, as well as gaining access to some gated communities and buildings.

Do mailmen have master keys?

They have the access code/PIN

Hence, most postal officers do not have access to a 'master key' as they used to. In turn, the mail carrier may request the building's manager to supply the code or pin required to access mailrooms or individual mailboxes (in the case of gated communities.)

How does USPS key?

If you have a key in your mailbox it is likely because you are using a Cluster Box. These units often have parcel lockers. The parcel locker is used for items that are too large for your individual box within the Cluster Box. The key in your mailbox is a parcel locker key.