This record represents 54 card covers or baffles for the IBM 7090 and related machines. The old 7607 data channel with the big handles in front originally came from a 7090 and uses these. When you pull the gates open, rows of these baffles are covering the circuit cards, making sure the cooling air goes all the way up. You have to remove a baffle to change a card, but all the other cards still keep cool. Each baffle has the numbers 1 through 28 marked along each of the rubber (long) edges. Half of the baffles have the numbers in reverse order ( 28 through 1).