The 10" Watts 757 Double Check Assembly began production in 2000 under the Hunter name. In 2002, Watts bought the rights to the device and began production as the 757 name. The body is made of stainless steel and uses a single sliding cover. Two victaulic clamps hold the access cover in place. The check assemblies are a plastic cam check design using a self contained torsion spring. All 757 devices are lead free. No special tools are required for servicing.