All Products › 1/2" Check Valve PN-110320 Image 1 of 2 Image 2 of 2 1/2" Check Valve PN-110320 $36.00 1/2” Check Valve used in-line with the fuel supply system to prevent loss of prime. Quantity: Add To Cart Added! 1/2” Check Valve used in-line with the fuel supply system to prevent loss of prime.