Pentair 191479 O-Ring Replacement Pool/Spa Valve and Filter<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>O-ring replacement</li><li>Fits Pentair Star Polymeric pool and spa D.E. filter models ST40， ST50</li><li>Also fits Pentair Star fiberglass pool and spa D.E. filters models ST40， ST50</li><li>Compatible with Pentair top/side mount multiport valves</li><li>Measures 1-1/8-inch length by 1/4-inch height by 1-1/8-inch width</li></ul></div><img src="http://ecx.images-amazon.com/images/I/41ktpK3BnML.jpg" noproxy>