I know electric over hydralic are availible but i don't know anything about them... I do know that Surge brakes are no longer legal( or soon will be) in WA on commercial vehicles (one tons pulling Bobcats and such) and most likely all surge brakes will go away. The article I read cited a number of problems with folks burning up their trailer brakes while compression braking... it also mentioned grandfathering in older ones or not...