Audio-Technica ATH-M50x Professional Studio Monitor Headphones (Certified Refurbished) This Certified Refurbished product has been tested and certified to work and look like new, with minimal to no signs of wear, by a specialized third-party seller approved by Amazon. The product is backed by a minimum 90-day warranty, and may arrive in a generic brown or white box. Accessories may be generic and not directly from the manufacturer.