The Makhoon back up valve Compatible with Zodiac Polaris models 180, 380, 280, 480 PRO, 3900 Sport, Vac-Sweep 380, Vac-Sweep 280, 280 TankTrax,Pentair E10New UpgradeCompared with the previous backup valve , we have upgraded the shell material, Made of crack-resistant polymer blend,which is more wear-resistant than the previous product, will not be easily damaged, and has twice the life span.G53 Gear MechanismMade of friction-resistant and stable POM material. Pom has a very low coefficient of friction and good geometric stability, especially suitable for the manufacture of gears and bearings, this material is more able to withstand high water pressure operation.FunctionThe Upgraded Version will solve the issue when your pool cleaner is stuck on an obstacle, although your backup valve is still open, water will no longer be sprayed from the nozzle, and keep the water out.Package Incldes 1 pc G52 Backup Valve Replacement Kit include G53 Gear Mechanism. And our worry-free 18-month warranty, For any reason you're not completely satisfied, you can ask for a replacement or full refund.