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Amazon.com: Midline Valve PVC Inline Check Valve for Backflow Prevention 1-1/4'' Solvent Connections White Plastic (4I2T114) : Industrial & Scientific
Amazon.com: Akozon Swing Check Valve 1" DN25 Check valve Stainless Steel One Way Female Thread WOG 200PSI for Water, oil, steam and other media and some corrosive liquids : Industrial & Scientific
Amazon.com: Pawfly 6 PCS Aquarium Check Valves for Common Air Pumps Red Plastic 1-Way Non-Return Valves Pump Protectors for Standard 3/16 Inch Airline Tubing Fish Tank Accessories for Aeration Setup : Pet
Amazon.com: Pawfly 3-Way Aquarium Air Flow Control Lever Valve Manifold for Air Pumps Fish Tank Multi-Port Distributor Splitter with 3 Non-Return Check Valves and 4 Suction Cup Clips : Everything Else
Amazon.com: DERNORD Sanitary Check Valve - One Way Flow - 1.5" Tri Clamp Style, Stainless Steel 304, FKM Gasket (1.5" Tri Clamp Check Valve) : Industrial & Scientific
Amazon.com: DN20 Female Thread 3/4 BSP Brass Check Valve, One Way Non Return Swing Check Valve 232PSI Prevent Water Backflow : Industrial & Scientific