From Amazon
VARTA Batteries Electronics V23GA Alkaline button cell battery 2-pack, Button cells in original blister pack of 2
Conrad Electronic
Varta ALKALINE Special V23GA Bli 2 Non-standard battery 23A Alkali-manganese 12 V 50 mAh 2 pc(s)
OnBuy
Varta V 23 GA MN21 Alkaline 12V Battery - 2 pack