This set of 100 o-rings is suitable for Seiko Colorpainter 64S / 100S, Océ CS6060 / CS6100 and HP Designjet 9000 / 10000 printers.
This is the original Seiko part (number 16-0031EP70). These o-rings are used in the ink lines and dampers.
These o-rings have an inner diameter of 3mm and an outer diameter of 6mm.