The Pentair JWPA JWP Ground Series is now used in pool and hot spa 1/2, 3/4, 1, 1-1/2 HP pump models. O-rings may cause swollen or cracked in-house pumps, but there is a pool vent in the back via sack air and SPIT, which can be replaced. No replacement O-rings, no damage. Please specify a 5" diameter measuring tape