Multi-unit mailbox manufacturers must have a multi-unit mailbox production supervision certificate or a postal appliance production supervision certificate. Multi-unit mailbox produced by regular manufacturers as long as the product quality is up to the standard and conforms to the multi-unit mailbox construction specification.

The production conditions that multi-unit mailbox manufacturers must have are as follows:
1. The enterprise must have the qualifications of an enterprise legal person;
2. The enterprise must have corresponding production sites and production equipment;
3. A complete quality management and quality assurance system is also a must for the company;
4. Have management and production personnel corresponding to production.
The relevant administrative departments of the postal industry shall conduct random quality inspections on various multi-unit mailbox products produced by enterprises that have obtained the multi-unit mailbox production supervision certificate, and publish quality notices in the provincial newspapers and the Beijing Post website.
Multi-unit mailbox production enterprises must accept the supervision and management of the municipal postal industry management department. When the administrative department of the postal industry inspects the production sites and sales premises of the production enterprises, the units inspected shall truthfully provide relevant materials and certifications. At the same time, the administrative department of the postal industry is obliged to keep confidential the materials and certificates provided by the inspected unit.
Enterprises that have obtained the multi-unit mailbox production supervision certificate must not engage in the following activities:
1. Reduce product quality and produce multi-unit mailboxes that do not meet standards;
2. Use expired production supervision certificate to produce multi-unit mailbox;
3. Transfer, lend, and sell the multi-unit mailbox production supervision certificate;
4. The enterprise shall not engage in other acts that violate laws, regulations and these Measures.