O-ring 13303 used on cover of the Injector Drain Module.
It's a round o-ring but fits the Oval shape of the injector cover.
* Also replaced 13303-01 used on drain fitting of Model 5810 and 7000 valves.
Also available in our SET of Orings 13303, 12638, 2 13301, 5600 Inj Module
listed as Related Product.