The 8" Watts 774XDCDA Double Check Detector Assembly was produced from 1998-2006. Very similar to the 774DCDA, the 774XDCDA uses smaller internal parts. The body is a single cover, stainless steel construction. The cover uses a victaulic style clamp. The check assemblies are self contained plastic cam style. The cam checks are bolted into the body. All 774 models are lead free. Bypass device would be a Watts 007M2 or 007M3. No special tools are required for servicing.