I lost several flashlights and other things, due to leaking batteries. AA ,AAA.

Now I found Panasonic Extra "Leak proof" (green colour).

Are they leakproof , or is it just advertising?

No doubt there is a bit of marketing going on. I guess these batteries are less likely to leak, will they never leak .... we will all have to wait and see.

Just remember the old saying: If the equipment is not in use for longer intervals, take out the batteries. Printed in about every manual.

Lithium batteries should be less likely to leak compared to the alkaline batteries. Not though that the lithium batteries can give more power to the electronic devices for longer time, which can fry the device.

http://www.energizer.com/batteries/performance-lithium/advanced-lithium/Pages/aa.aspx

http://voices.yahoo.com/benefits-lithium-batteries-2230667.html

http://www.candlepowerforums.com/vb/showthread.php?332304-Lithium-vs-Alkaline-AA-batteries-leaking-potential

EDIT to previous: It seems that the frying of electric devices, which have not been designed well, is due the lithium battery have a bit higher initial voltage (1.7V) and less internal resistance, which can allows high tech device to draw lot's of current from the batteries while charging for example capacitors. Some EE might give a better answer.

Frying with Lithium batteries

http://www.tomshardware.com/forum/36095-5-lithium-batteries-recommended

Batteries do not last here in think its the high humidity

Buy the cheaper ones and replace them on a regular basis, thats what we do with remote controls

even duracell which i always bought if available do not last more than 6 months

Strange you should mention it, my remote on one of the TV's stopped working, so when i went to change the batteries, yes you've guest it, the batteries had leaked all over the inner casing of the remote, no real problem, but it does happen a lot with batteries over here