Check Valve Cartridge, 2/pk Back Catalog number: CTS-A094 Manufacturer: SCIENCIX Availability: 3 weeks Price on request - + Recommended CTS-A11145 Tube Assy, System Outlet, SDS Price on request CTS-10597 Wash Tube Seal Kit, 4/pk Price on request CTS-21089 Needle Seal (For pH 1-14, for operation up to 130 Price on request