LIP-4WM genuine Sony 'Gumstick' (Sony LIP4WM, Sony LIP-4WM) 370mAh Li-Ion. Audio battery.
USB-C Charger for Lip-4WM : r/minidisc
My first LIP-4WM build - and it works!, yay! : r/minidisc
Your Sony Hi-MD player deserves longevity. These lip-4wm compatible battery is your answer. They are also 500mAh vs. 370mAh (original Sony). The search is finally over. Selling for €20 plus shipping. Shipping