The Apollo DCDA-4A is a double check detector assembly (DCDA). It is available in 2 1/2″-12″ sizes. It 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. A lead free version was introduced in 2011. The DCDA-4A utilizes a Type I or Type II bypass.