CAT-501S is professional in cleaning the auto transmission with the detergent added and exchanging the auto transmission fluid simultaneously with the engine on when there is pressure difference inside the auto transmission and the pump. It also has the function of auto transmission fluid flow automatical recognization, frequently-used vehicle adding and searching list, fluid exchanging result customerized printing, fluid filter replacement warning. Moreover, with bigger 5 inch display and optional VGA function, the presentation and operation will be more easy and vivid.