This handy bypass kit is designed for use with the AquaQuick SolarPRO XD1, XD2, and XF swimming pool heaters on all in ground pool applications and pump and filter systems with 1 HP or greater. It should also be used when connecting 2 or more heaters together. Water flow is restricted when passing through these heaters and with larger horse power pumps it is necessary to bypass some of the water so you can control the flow and direct some of it past the system. The slower moving water in the heaters will collect more heat and your equipment will run more smoothly. You can also bypass your solar heaters if you run your pool at night to optimize flow and so you don;t cool the pool off. Each kit comes complete with a 2-way valve, T-fitting, and all other fittings to make a complete bypass system.