Check Valve Cartridge, 2/pk Back Catalog number: CTS-10493 Manufacturer: SCIENCIX Availability: 3 weeks Price on request - + Recommended 11-4122 PTFE Diaphragm, LC-30AD/i-Series, 2/pk Price on request CTS-21089 Needle Seal (For pH 1-14, for operation up to 130 Price on request CTS-A094 Check Valve Cartridge, 2/pk Price on request