From the website:
"Thank you for your purchase of a Certified Pre-Owned Dolphin pool cleaner! You have made a wise choice! All certified pre-owned Dolphin cleaners have been thoroughly inspected and re-conditioned by our own Maytronics factory trained technicians. We adhere to a strict 12-point inspection system to ensure that your Dolphin will meet both your expectations and ours.
Replacement of wearables, such as filters (bag, basket or cartridge), tracks, brushes and climbing rings are NOT covered under this 12 month limited warranty.
Certified Dolphins is an official Maytronics site – makers of the Dolphin line of robotic pool cleaners. Certified pre-owned Dolphins come with a limited one-year warranty and meet the following criteria."