Can I use 14500 to replace 2x AA battery?

I ordered some overspec ebay laser pointer.

Someone suggested to use 10440 battery to increase output. However, I have some 14500 battery lying around at home.

1) Can I use 14500 to power instead of 10440?
2) If I can use 1x 14500, do I buy this dummy AA to fill up the space?

1) the voltage is the same so both are usable if the laser can fit the larger 14500 cell.
2) you can use any dummy you like as long it fits.