The American Plumber W38-OR O-Ring is a replacement o-ring for all American Plumber 3/8" I/O Filter Housings, WLCS-500 Undersink System, and WRO-3167 Reverse Osmosis System. American Plumber Part 152031. Fits 3/8" Slim Line Housings.
This O-ring is also known as the Buna-N #237 and 237-7470-10. Part number 151121 by Pentek, Ametek, Pentair. This o-ring also replaces the Pentek o-ring 158648.