Both work well! Only the headphone jack is untested. I refurbished the yellowed one, it had corrosion but is now working corrosion has been removed, all flaws shown, appears to have a broken headphone jack on the same yellowed one. Both dance and seem to have working sensors. Batteries not included. The white iDog has some minor blue staining on the back, but otherwise is in decent shape. As-is.  Will not separate.