This is a World War II US Army Signal Corps PG-102/CB two-bird pigeon carrier. This carrier was used to transport pigeons during WWII. The top opens up to a compartment for message books, capsules , etc. The bottom opens for cleaning. When you open the top you can raise the bars to release the pigeon. There are holes in the sides that allow access to the pigeons leg to attach the message capsule. The box measures 13 1/2" long, 7 1/2" wide, 9" tall. This carrier is unpainted with the exception of OD green edged in under the hardware. The lip is stamped PG-102/CB.