Protected-dual protected, what's the diff?

[TeaSipper]

I have 2x18650 Simon (made by Panasonic) batteries, works very well. As the question above, what's dual protection?

http://www.amazon.com/gp/product/B00TCRZDJA/?tag=cpf0b6-20

 

[zipplet]

Marketing. At a guess, they are referring to the fact that as the battery cell is a quality cell it has some protection internally (PTC, vent valve) and in addition to that they have added a protection PCB - hence "dual" protection.

 

[TeaSipper]

Thanks, that makes sense.