This durable unit is manufactured from tough aluminum with corrosion resistance, giving you a unit that will last for many years. It is USPS approved and is designed with 7 business doors, two master lock doors, and two 15" parcel lockers. These business doors are bigger than standard 4C mailbox doors, making it easier to accommodate large volumes of mail. It meets STD-4C requirements for new construction and renovations. These mailboxes feature heavy duty dustproof cam locks on each door to keep the mail inside safe and secure. Invest in a mailbox that has the features you need to help your business run more efficiently.