GVCVHVCV 9985006-r2 Track and Climbing Rings 6101611-r4 Replacement Parts Compatible with Maytronics Dolphin Nautilus cc Plus Robotic Pool Robot (6 Pack)Brand: GVCVHVCV Color: White Features: 9985006 R2 TRACK REPLACEMENT PARTSCompatible With Numerous Maytronics Dolphin Robotic Pool Cleaner Models, Compatible With Dolphin DX Dolphin Explorer Dolphin Apollo Dolphin Wave Dolphin Nautilus Dolphin Advantage, and more. 6101611 R4 ROCK CLIMBING RING REPLACEMENT PARTScompatible with robotic pool cleaners like DX3, DX4, DX6, M200, M400, M500, Atlantis, Apollo, Apollo Plus, Nautilus, Nautilus CC Plus, Oasis