In-Line Check Valve Save Liquid error (snippets/product-badge line 32): Computation results in '-Infinity'% $8.95 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Use this In-Line Check Valve to prevent the possibility of back flow from your Kegs. The Check Valve includes one 1/4" MFL and one 1/4" FFL fitting. Use this In-Line Check Valve to prevent the possibility of back flow from your Kegs. The Check Valve includes one 1/4" MFL and one 1/4" FFL fitting.