A 14500 Li-Ion is roughly the same size as an AA battery, but that's pretty much where the similarity ends. If you put a 14500 in your radio, shaver or... bedroom appliance... a burning smell will signal the end of your relationship. This is because the voltage of a 14500 can be up to three times higher than an AA (and this is probably a good time to mention that I take no responsibility for any damage or loss arising from the use or abuse of anything I supply).
However all of my 14500 torches play very nicely with AA batteries, so "alkalines" can be very useful as backups, although for peak performance you'll need that little Li-Ion. Click on the pictures below to see details of my batteries and drop me a line to discuss discounts.