he Onyx Duckbill Check Valve is reliable and cost effective flow control solution. These products are 100% rubber heat molded products that are suitable for almost any environment. These products are maintenance free and have no mechanical components. Their revolutionary design eliminates the need for an outside energy source, will not warp, freeze, or clog. Their virtually silent functionality make them great for any application so stop wasting money on costly repairs to gate valves and damage done due to backflow and give Onyx a call to create a cost effect control solution for you.