What is a battery spacer?

A size-conversion spacer for AA rechargeable batteries is an extra casing which can temporarily convert your AA batteries to C or D size.
More specifically, you insert an AA size battery into a C or D size type of spacer and temporarily use it for appliances operating on C or D size batteries.

However, please take note of the precautions mentioned below since size and characteristics between the spacer and the original battery are different.

1. Do not use spacers continuously as they are meant for temporary use.
2. It could be the case that spacers cannot be used due to  different characteristics between batteries
3. It could be the case that the spacer does not fit in the appliance due to a slight difference in shape between spacer and designated battery
4. When needing more than 1 battery, do not mix spacers with rechargeable batteries inserted together with alkaline batteries of the same size. 
5. When using more than 1 spacer, do not use batteries which are not the same in terms of capacity, brand name, production date or remaining capacity.
6. Please only insert a spacer into an appliance when you need to run the appliance. Remove the spacer and store it separately from the inserted battery when you have finished using the appliance
7. The operating time of an appliance using a spacer is shorter than that of the same appliance using the correct C or D dry battery.
8. Please do not try to charge a battery when it is inserted into a spacer
9. Only use rechargeable batteries in spacers and not alkaline batteries