Maytronics Robotic Pool Cleaner Replacement Bottom Lid Spring Manufacturer Part # 9982331 Fits the Following Cleaners: Dolphin Nautilus Dolphin Triton Dolphin Dx3 Dolphin Dx4 Dolphin Dx3 Cb Dolphin Dx4 Cb Dolphin Dynamic Dx6 Dolhpin Deluxe 3 Dolphin Deluxe 4 Dolphin Deluxe 5 Dolphin Saturn Dolphin Edge Dolphin apollo Cb Dolphin Atlantis Basic Cb Dolphin Apollo Windo Dolphin Dx4 Dyn Pentair Prowler 830 Spectra Light Premier Cb