Why cant you use a AAAA Battery instead of 2 AA Batteries.? - Quora
AAAA Battery - Pack of 2 | eSpares
Duracell Aaaa 1.5v Batteries | Long Lasting Specialty Alkaline Battery, 2 Count : Amazon.ca: Health & Personal Care
Duracell Specialty Alkaline AAAA Battery 1,5V, Pack of 2 (LR8D425) Suitable for use in Digital pens, Medical Devices and headlamps : Amazon.in: Electronics