Manufacturing inspection stamp (stamp of approval)
overall: 1 1/4 in x 4 in x 4 in
This is one of four rotors related to an ENIGMA encryption/decryption device, but does not match the serial number of B197.81 nor B198.81. However, it does match the serial number on rotor 102616399 which suggests they were made for the same machine. Stamp of approval (inspection) marked with a Nazi swastika. Screws used on this rotor have a rounded head and last number '8' in 'A 1898' is marked red.
Per Ralph Simpson of the Cipher History Museum, "The 'A' indicates use by the German Army and Air Force (Navy used 'M' for marine)." [2016-05-09].