The Apollo DC-4AN is a double check valve assembly (DCA). It is available in 2 1/2″-12″ sizes and has been in production since 2008. The 2 1/2″-8″ body is made of stainless steel. The 10″-12″ body is made of ductile iron with a fused epoxy coating. The DC-4AN is an “N” shaped device. A lead free version was introduced in 2011.