The object is a metal panel with sockets for 12 octal tubes (6 populated, 6 vacant) on the front and a number of coaxial connectors on the back. Also on the back are 2 more unpopulated sockets. An etched label on the upper left and also on the rear of the panel read 303 B REGISTER DIGITS 0-15 SERIAL # 19. Partly obscured on both labels is "403 in out register." Example labels on the coaxial connectors are J14 TO CHECK BUS, J11 READ TO BUS, and J17 FROM BANK A.