Really any of them like the 223 mentioned above by Littlefuse will work as long as you are not using a Cycle Stop Valve. Most of these devices look for a 25% drop in amps to shut the pump down on dry run. 25% is fine as long as you don't have a CSV. But when using a CSV the amps may drop by 50% when the CSV is working the pump at low flow and the Dry run protector will think the well is dry and shut the pump down. We made the Cycle Sensor so you could set it for 55% amp drop and it would know the difference between the CSV working and actually pumping the well dry. There are not many 3HP or larger pumps in weak or low producing wells anyway, so the larger Cycle Sensors were not very popular like the 2HP and smaller ones are. As long as the well is a good producer you can use a Cycle Stop Valve and not need the dry well protection.