CS OEM Medium Adjustable Back O-ring (6 Pack) - 257426
THIS IS AN AUTHENTIC GRACO PART
This is the o-ring that goes onto the selector knob on the CS adjustable back. it is the middle size of the three o-rings that go onto the part.
This o-ring is also used as the large o-ring on the dosing piston.
Sold as a 6 pack