Polaris 3900 Sport / Vac-Sweep 380 / 280 / 180 / 280 TankTrax / TR35P and Quattro Sport Pressure Cleaner UWF Restrictor Kit Polaris 3900 Sport / Vac-Sweep 380 / 280 / 180 / 280 TankTrax / Trade Grade TR35P and Quattro Sport Pressure Cleaner UWF Restrictor Kit The UWF restrictor kit is replacement parts that are made by Polaris. they use the same high-grade materials that were used to make the original factory parts. Making them genuine OEM products. This restrictor kit includes the universal wall fitting and two flow restrictor disks if needed (not usually). These are meant to restrict or reduce the flow from the booster pump allowing the cleaner to operate correctly. In some cases without these parts the flow of water may be too high which would overpower the cleaner and make it ineffective. These parts are different in color but easy to identify as the UWF is black or white and the restrictor disks are blue and red. This helps you identify which part may need to be purchased when needing to be replaced.