Check Valve Cartridge, Ceramic, 2/pk Back Catalog number: CTS-21463 Availability: In the manufacturer's stock Price on request - + Recommended CTS-21089 Needle Seal (For pH 1-14, for operation up to 130 Price on request CTS-21585 PM Kit, 1220 Price on request CTS-10711 Alliance Head Plunger Seal Kit, Black, 2/pk Price on request