A disk platter mounted on a wooden base reading "350 IBM San Jose Disk Storage Progress" with various disk head sizes silkscreened onto lower half. Disk head sizes shown are: 1311, 2311, 2314, 3330, 3330-11, 3340, 3350, 3310, 3370, 3375, 3380, all of which refer to IBM models of disk drive.
