STD-4C or STANDARD-4C refers to a set of standards and regulations set by the United States Postal Service regarding the specifications of cluster mailbox units used in new construction. All multi unit constructions building plans submitted after October 6, 2006 are required to use STD-4C compliant mailboxes STD-4C mailboxes The STD-4C is the current USPS regulation for any centralized, wall-mounted mailboxes, whether located inside an office high-rise or within a new single-family subdivision as an outdoor centralized mailbox kiosk. New STD-4C compliant mailboxes are commonly referred to as centralized mail delivery equipment. The Postal Service modified the regulation for new construction due to changing customer mailing habits and specific mail and package volume trends. Postal Service statistics indicate customers receive more mail and of varying sizes than at the time of the last updated standard which prescribed design limitations that are no longer consistent with the operational requirements of the Postal Service. The new standard (which became mandatory in October 2006) requires mailbox receptacles with increased protection for the mail, benefiting both senders and addressees; improves the overall safety of the equipment in use; reduces maintenance costs incurred by buildings; and results in cleaner lobbies with less clutter. Finally, the newly designed receptacle is easier to access and serve by carriers, thereby helping to reduce Postal Service costs and becoming the "greenest" delivery method. Developing a new standard: The new standard was developed through a consensus process and was agreed to by a committee of representatives from mailbox manufacturers; mailbox distributors; mailbox installers and servicers; Postal Service customers; multi-unit residential and commercial property builders, owners, and managers; and the Postal Service. In addition, Domestic Mail Manual (DMMTM) standards provide manufacturers and customers with notice of the specifications. The members of the committee met six times as an advisory group and negotiated among themselves and with the Postal Service to reach a consensus on a new standard. Committee members were selected for the purpose of, and accepted the responsibility for, representing other interested individuals and organizations that were not present at committee meetings and to keep them informed of the committee's proceedings. As part of the consensus process, the Postal Service agreed to use a recommendation by the committee as the basis of the revised standard. Standard 4C represents the committee's recommendation. With one exception, each member of the committee signed the final agreement recommending adoption of this standard. That one