The 10" Watts 772 Double Check Assembly was produced from 1993-1997. Very similar to the 770, with exception to the shutoffs. The 772 uses a special sgutoff that are not standard. Two different sizes on the flanges make it unique. The body is a two cover, epoxy coated ductile iron construction. The check assemblies are stainless steel toggle linkage type. They use a vulcanized clapper plate. Check springs are contained when the cover is removed. Spring tension must be removed to repair the device. The device has replacable bronze seats, but a seat removal tool is required.