These have all been tested and work with a AAA battery This lot of 10 play away portable audio books come with 5 headphone sets and 10 lanyards to carry them with you Included an extra that is soft tranquil music , has no backing for the battery . Small lightweight and portable Out of my personal collection , I kept a few on display on my own bookshelves The one with the lanyard is one of my own, added to show how the lanyard is placed , the battery placement and how the screen looks when on. It’s fun and amazing unique bookish lover item . There may be some shelf wear