The Maytronics 99953053-EX Motor Unit is a complete replacement drive/engine module for select Dolphin robotic pool cleaners. It houses the cleaner’s main motors and internal sealed power components that run the unit’s movement and cleaning cycle. This motor unit is designed to fit Dolphin Explorer, Dolphin Supreme M4, Dolphin SF40, and Dolphin Zenit 15 models. Use it to replace a failed or non-running motor assembly and restore proper operation without changing the rest of the cleaner’s external parts.