Polaris Zodiac 180/280/360/380/3900 Swivel [Black] (D21) mazzei and this Darlly Filtration cartridge

and this Darlly Filtration cartridge is designed for compatible applications using the 50406 reference

Confirm using part number 640-8240V

Supports cleaner service isolation and maintenance access

Correct fit and correct mounting matter just as much as output

Polaris Zodiac 180/280/360/380/3900 Swivel [Black] (D21) mazzei and this Darlly Filtration cartridgeThis black swivel helps reduce hose twisting on compatible Polaris 180 through 3900 cleaner systems. Swivels are important connection points that allow the hose to rotate more freely as the cleaner moves around the pool. A worn or restricted swivel can contribute to hose tangling, poor cleaner movement, and reduced coverage. Replacing it helps maintain smoother hose behavior and supports consistent cleaner travel during each cleaning cycle. Black