The back up valve Compatible with for Zodiac models 180, 380, 280, 480 PRO, 3900 Sport, -Sweep 380, -Sweep 280, 280 TankTrax, E10 New Upgrade: Compared 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 damaged, and has twice the life span. [G53 Gear Mechanism]Made of friction-resistant and stable material. has a very low coefficient of friction and good geometric stability, especially suitable for the manufacture of gears and bearings, this material is more to withstand high water pressure operation. [Function]The 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 ]2 pc G52 Backup Valve Replacement Kit include G53 Gear Mechanism. Material: plastic colour: White Package Contents: 2 x G52 Backup Valve Replacement Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.