StaRite 2in Sidemount Multiport Valve Cover O-Ring, 14971-SM20E7

No. 5 Image 14971SM20E7 aka 14971-SM20E7, Genuine Sta Rite Valve Cover O-Ring, 2 in Used on Sta-Rite (Pentair) Side Mount Multiport Valve Series, models 18201 / 18202.
14971-SM20E7 can also be found on StaRite 1.5in Multiport valve parts pages.