The Maytronics 99953033-EX is a replacement motor unit with impeller for Dolphin robotic pool cleaners. It houses the drive motor assembly that powers the cleaner’s movement and water flow through the internal pump/impeller, helping circulate debris into the filter system during a cleaning cycle. This is a Maytronics-certified genuine part made for use with the Dolphin Nautilus (including legacy/older Nautilus models), Dolphin Quest, and the Prowler 820 robotic cleaner. Covered by a 1-year motor-unit warranty.