This is the best summary I could come up with:

As noted by Valve, "Each Certified Refurbished Steam Deck has been thoroughly tested to the same high standards as our retail units.

Every device goes through a complete factory reset, software update, and an extensive examination involving over 100 tests at one of Valve’s facilities.

Battery health is also assessed to ensure proper functionality and longevity.

Although they may have minor cosmetic blemishes, they provide a reliable, high-quality gaming experience at a lower cost."

They all include the same full one year warranty as a brand new Steam Deck, a refurbished power supply and carrying case.

In the FAQ at the bottom Valve also notes that stock levels will come and go over time, as they are selected from customer returns that “pass rigorous criteria”.

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