This Subco uses a Positive Temperature Coefficient Relay (as stated on their website) not a Potential Relay.  Not Good!  Only use Hard Start Kits that use a true Potential Relay. The RectorSeal Kickstart (2 wire) and the 5-2-1 Compressor Saver (3 wire) hard start kits use a Potential Relay. I recommend the Kickstart (it uses 2 wires that connect to the Run Capacitor - HERM and COM). But the Compressor Saver is also good (3 wires with one connecting to the common / ground on the Contactor relay). They both work the same way - the Potential Relay detects the pickup voltage (back EMF). This causes the relay to disconnect the start capacitor when the compressor reaches about 75% speed (usually less than a second).  Note:  Supco does have hard start kits with a Mechanical Potential Relay (Models 3W1, 3W2, & 3W3).