This one need to check .... looks like Ni-MH 1/3 AAA (x2) .... you might try to use 2 pcs of those battery taken from small RF R/C car from Ap Liu street ..... those "can" car for $40 ~ they have a 1/3 AAA Ni-MH inside .... let me check with Japan side tomorrow ...see see if I can find that battery info for you ~