The 6" Watts 774 Double Check Assembly was produced from 1998 and is still currently in production. 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 thread into the body. The cam checks are self contained and disc rubbers cannot be replaced. All 774 models are lead free. No special tools are required for servicing, but a handy cam check removal tool is available to assist in removal of checks.