Salsbury 3300 Series Cluster Box Units (CBU"s) - U.S.P.S. Access. Salsbury Industries is officially licensed and authorized by the U.S. Postal Service to manufacture Cluster Box Units (CBU"s). Manufactured by Salsbury Industries to U.S.P.S. "F" Specifications. License # 1CDSEQ-08-B-0026. Ideal for commercial and residential developments. Include matching pedestal. Constructed of heavy duty aluminum and stainless steel hardware. Feature a durable powder coated finish available in sandstone, bronze, green, black, white and gray (for replacement units only). Accessed from the front through 2 easy opening master door panels. Available in "A" size doors (12-3/4" W x 3-1/8" H) and larger "B" size doors (12-3/4" W x 4-7/8" H). Doors include a heavy duty 5 pin cylinder cam lock with a dust/rain shield and 3 keys. Salsbury Industries is an ISO 9001: 2008 certified company and has excelled in the field of manufacturing since 1936.