Compatibility: The G52 relief valve is compatible with Zodiac Polaris Pool Cleaner 180, 380, 280, 480 PRO, 3900 Sport, Vac-Sweep 380, Vac-Sweep 280, 280 TankTrax. New Upgrade: Compared with the previous safety valve, we have improved the shell material, made from anti-crack polymer blend, which is more wear-resistant than the previous product, will not be not easily damaged and has twice the lifespan. Fixed Issues: We checked some common issues and made some improvements. In addition, if you encounter the following situations, get stuck in reverse position, continuously discharge water, do not work, and show signs of explosion, the gear may work; If it is caused by misalignment in the middle, please open the case, check whether the external gear of G53 is misaligned and repair it. G53 gear mechanism: Made of wear-resistant POM material wear and stable, it can work continuously under ultra-high water pressure, but if there is too much sand, the gear will be stuck. At this point you need to remove the grinding wheel to clean the sand and continue working. Don't mention: Buyers reported that continuous spraying of water caused the Polaris to float because the local water pressure exceeded the adaptive water pressure too much. We have made improvements. Note: The data is all measured manually, please allow 1-3cm error due to differences in light and display, there may be color differences , please refer to the actual item received.