Wide Compatibility: Compatible with Zodiac Polaris 180, 280, 380, 480 PRO, 3900 Sport, Vac-Sweep 380, Vac-Sweep 280, and 280TankTrax models. Provides Sufficient Relief Pressure: Made of stable and friction-resistant POM, this relief valve is sturdy and durable. It prevents your robot from getting stuck or tangled. The G52 relief valve is ready to install. Simply connect the fittings and hoses firmly to operate it. It opens every 3 minutes for 30 seconds to extract the robot and reverse its cleaning direction. This valve also helps clear the unit from hard-to-reach areas. It is also suitable for saltwater pools. Compared with the previous relief valve, we have improved the shell material: a crack-resistant polymer blend, more wear-resistant, more resistant to damage, and twice as long a service life. Note: If the product does not work properly, disassemble the replacement valve to check if it is stuck in the gear. After cleaning and reinstalling it properly, it can work normally.