These controllers work with 12-Volt pumps to provide precise control over a wide RPM range. Dial in the desired operating pressure and the pump will maintain a constant flow. The 10 amp units are complete with tube, cables, and an unmounted stainless gauge. 25 & 35 Amp units include the same plus a built-in gauge and 2 year warranty. These controllers have a soft start feature and are reverse polarity protected.