The Ames Maxim Series Double Check Valve Assemblies are constructed of stainless steel. Similar to the Colt Series, the Maxim uses larger interior parts for increased flow rate. The Maxim Series is offered in a number of configurations with many valve options. To access the check assemblies there is a stainless steel sleeve that will slide open. On the 2 1/2 - 6" you must unthread the #3 test cock then slide the cover. 8 - 10" uses two victaulic clamps to hold the stainless sleeve. The Colt uses two self contained cam checks that use a tri-link check mechanism. Numerous repair parts are available for the Colt series devices, including rubber parts and complete parts. There are no special tools required for service.