Blue IBM Selectric ribbon cartridge
International Business Machines (IBM)
||"Reorder No." printed on the back of the ribbon in white.
||Printed in white on the back of the ribbon cartridge below the reorder No.
overall: 3/4 in x 3 3/4 in x 2 in
"Medium blue nylon" is printed on the back of the cartridge in white. There are two spools in the center of the cartridge for winding the ribbon.
Gift of Donald Knuth