WC207: Tool for removing check valve compression disc on Ames 6″ to 10″ C200(A), C300(A), C400, C500, Ames 4″ to 10″ M200(A), M300(A), M400, M500 & Watts 6″ to 10″ 757(A), 757(A)DCDA, 957, 957DCDA. This is the best way to hold the check open when changing the rubber gasket on the check.