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 captures fine sand, algae, leaves, and other small debris from swimming pools. 2. Durable Construction: Built with an ABS plastic frame for long-lasting performance. With proper care, these filters can last 2 to 3 years. Compatible Models: Delphin Nautilus CC Plus, Maytronics Dolphin 9991432, Dolphin M400, Dolphin M500, Delphin M4, Delphin M5, Delphin Orion, Deluxe 3, Atlantis, Apollo, Apollo Plus, DX3, DX3s, DX4, DX4s, Sigma, Odyssey, Oasis Z5i. Tips: 1. Rinse the filter every 4 to 6 weeks to maintain optimal performance. 2. Always follow the filter user manual when replacing or cleaning the filter.