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What are Cluster Mailbox Units and How Do They Work?

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What are Cluster Mailbox Units and How Do They Work?

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You may have seen the abbreviation CBU before. Cluster Mailbox Units are also just called cluster mailboxes in many cases.

This mailbox type is meant to serve multiple families or businesses, and come in “clusters” of mailboxes mounted on a pedestal. Often, between eight and sixteen horizontal mailbox compartments are included in each CBU, and they are locked for security. There are also up to two parcel lockers, also locking, included with these setups. These units are for outdoor use only and are often used when durability and security is needed, since they are made of durable construction. These mailboxes are found mounted on pedestals which in turn are mounted on a concrete slab.

Cluster mailboxes are typically used to handle USPS delivery for apartment complexes and multiple businesses. They’re also appearing in newer neighborhoods in recent years. They’re best placed in a central location for apartment complexes and in an easily accessible area for businesses. CBU’s are a viable choice when there is not much space for other types of mailboxes, or no clubhouses or kiosks available. Cluster mailbox units can be placed side by side. However, each CBU will need its own concrete slab.

For delivery, a USPS employee will have a master key that will open the entire CBU and allow the delivery of mail and packages to each customer. The lock that the USPS employee uses to deliver to all customers is known as the arrow lock.

If a customer receives a package that must be placed in a parcel locker, the postal employee will leave the customer a key to the unit with the customer’s other mail. The customer is then able to safely access their package, and the key is retained in the lock for the USPS employee to retrieve the following day.

Like other types of residential and commercial mailboxes, CBU’s must be approved by the post office and must meet USPS regulations to receive mail delivery. However, CBU’s are typically made with these regulations in mind, though any locks must be installed by a USPS employee.