Parts - Ultra fine filter cartridges 9991432-R4 for Maytronics Dolphin pool robots, compatible with Delphin Nautilus CC Plus, M400 and M500.Product Features: 1. Ultra Fine Filtration: Pleated filter media is used to filter all types of ultra fine debris in swimming pool, such as fine sand, algae, leaves, etc.2. Durable and durable: ABS plastic frame, more durable.When properly applied, these ultra-fine filters can last 2-3 years.Ultra Fine Filtration: Pleated filter media is used to filter all types of ultra fine debris in the swimming pool, such as fine sand, algae, leaves, etc.Durable and durable: ABS plastic frame, more durable.When properly applied, these ultra-fine filters can last 2-3 years.Compatible models: For Delphin Nautilus cc plus filter. For Maytronics dolphin parts 9991432. For dolphin M400 M500 filter. For Delphin M4 M5 pool cleaner. For Delphin Orion, Deluxe 3, Atlantis, Apollo, Apollo Plus, DX3, DX3s, DX4, DX4s, Sigma, Odyssey, Oasis Z5i filter.Tips: 1. Please rinse the filter every 4-6 weeks for optimal performance.2. Please always follow the filter user manual when changing filters.