Maytronics Dolphin Ultra Fine Cartridge Filter | 9991432-R4Maytronics 9991432 R4 Ultra Fine Debris Filter Panels (4 Pack, Large Spring Style) for Dolphin Robotic Pool Cleaners Genuine Replacement The Maytronics 9991432 R4 is a genuine Dolphin ultra fine debris filter panel kit that includes 4 replacement filter panels. These are commonly listed as large spring style ultra fine filter panels used in compatible Dolphin robotic pool cleaners to capture very small debris such as dust, silt, sand, and algae. Key