WWII US Navy Model OBU-3 Echo Box Test Set SHIPS 308-A Manual 1944 Confidential Back-to-School 22 rimfire

22 rimfire

Manufactured by Allen B

secured by canvas straps and metal hardware

Please review photos carefully for overall condition and exact configuration

WWII US Navy Model OBU-3 Echo Box Test Set SHIPS 308-A Manual 1944 Confidential Back-to-School 22 rimfireOriginal Preliminary Instruction Book for the Model OBU 3 Echo Box Test Set (SHIPS 308 A), manufactured for the U. S. Navy Department, Bureau of Ships by Johnson Service Company, Milwaukee, Wisconsin. This manual is dated June 15, 1944 and is marked Confidential (Non Registered), making it an interesting piece of WWII U. S. Navy electronics and radar test equipment history. The manual relates to the OBU 3 Echo Box Test Set used in the maintenance and