Specifications: Black Material: Foam Filter Outer Diameter: 4.3 cm Inner Diameter: 1.4 cm Length: 7.3 cm Compatible with Robots: Polaris 180, 280, 360, 380, 480 Pro, 3900 Sport Dimensions: Outer Diameter: 4.4 cm; Inner Diameter: 1.3 cm; Length: 7 cm Easy Installation: Simply remove the worn brush, then replace the new hose tail cleaner. The pool tail can replace worn pool cleaning rings to ensure algae, dirt, and debris are removed from the floor, walls, and stage areas in the pond area. Package Includes: 10 Foam Brushes Product Description Northern Zodiac Polar Star Model: 180, 280, 360, 380, 480, and 3900. Compatible Part Number: Polaris 91003105/9-100-3105/PP-91003105.