This Maytronics Dolphin™ 9997020-R1 Diagnostic Tester Tool for Dolphin™ Robotic Pool Cleaners is a reliable replacement part, designed to seamlessly intergrate with the original pool cleaning system. The diagnostic test tool is important to ensure that the pool cleaner is operating properly. Maytronics pool cleaners help keep your pool healthy and clean, which is of the utmost importance. Ensure that your pool cleaner is running as cleanly as possible with this certified genuine part.