1. Compatibilty:G52 Backup Valve fits Zodiac Polaris Pool Cleaner 180, 380, 280, 480 PRO, 3900 Sport, VacSweep 380, VacSweep 280, 280 TankTrax. 2. Upgrade:Compared with the previous backup valve, we have upgraded the shell material, Made of crackresistant polymer blend, which is more wearresistant than the previous product, will not be easily damaged, and has twice the life span. 3. Fix the problem: We have checked some common problems and made some improvements. In addition, if you encounter the following situations, it is stuck in the reverse position, the water is continuously discharged, it cannot work, and there is an omen of explosion; it may be that the gear is working If it is caused by the dislocation in the middle, please open the casing, check whether the external gear of G53 is dislocated, and correct it. 4. G53 gear mechanism: Made of wearresistant and stable POM material, it can work continuously under ultrahigh 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 to continue working. Don't mention: the continuous water spray from the buyer feedback caused the problem of Polaris floating because the local water pressure exceeded the adaptable water pressure too much, and we have made improvements.