Compatible robots: Polaris 180, 280, 360, 380, 480 Pro, 3900 Sport, compatible with Polaris 91003105 / 9-100-3105 / PP-91003105. Size: Outer diameter: 4.3cm; Inner diameter: 1.4cm; Length: 7.3cm Easy to install: Simply replace the worn tail scrubber with a new tail brush at the end of the tube. EFFECTIVE CLEANING: These filter absorbent sponges contain uniform parallel holes to effectively capture large debris and particles and remove pool cleaner residue. They also help scrub the floor and sides of the pool. Great value: 20 foam brushes, no need to change them weekly.< /p>