C.I. Thornburg serves the municipal water and wastewater industry in all of West Virginia, Kentucky, Tennessee and the southern part of Ohio. They offer swing type gravity operated check valves in sizes from 2 1/2" through 24". Thornburg also offers swing type lever and weight types with the same basic features. Both styles come with either FL. x FL. ends or M.J. x M.J. ends. Swing type spring and lever check valves are available with either adjustable weight or adjustable spring tension to control opening and closing of the clapper.