Any equipment used to hold more than one mailpiece. The term includes a sack, pouch, hamper, nutting truck, basket, letter or flat tray, and a variety of boxes and carts. Mail transport equipment used to move mail inside a plant or between authorized postal facilities can also be described as containers. This includes Amtrak containers, Bulk Mail Center Over-The-Road (BMC-OTR) containers, BMC in-house containers, CON-CON containers, multipurpose containers (eastern region mail and general purpose mail containers), and wire containers.