Oring used with Air Check - New Style used from about 1993 to present. Used on late model Autotrol 155 and all 255 water softener valves. NOTE: Air Check - New Style Kit 1032416 - AP1032416, Comes with this Oring, so you don't need to order it separately.Cross reference old PN
# 40A220) = model Technetic 1000
