Bill, which one of the two did you get? Neither say 20 hours of light. One says 16 hours, and the other says 40 hours.
....Oops.....nevermind. I figured it out. I am intrigued, but I have also been looking at these:
http://www.biolitestove.com/campstove/c ... /features/
The Biolite stoves are also being marketed in the same manner, and for the same purposes, as the WakaWaka lites - international charitable giving. These are "wood gas" stoves which have a small fan that helps the efficiency of the wood burning, making it so that a very small amount of wood can produce a large amount of heat to cook by. I have such a stove in my bugout bag, but mine requires an AAA cell to power the fan. But the Biolite wood gas stoves are different in that they harness the heat produced by the burning wood to generate an electrical charge which both powers the fan AND can be used to recharge a phone or other electronic gadget via a USB port.
Buying these stoves funds the distribution of a larger version of the stove, called a "HomeStove", to underdeveloped areas. The need is that much of the cooking in these areas is done over smokey fires, inside a primitive dwelling, and the smoke from the fires harms the health of the dwellings' occupants. These stoves work in pretty much the same way as the smaller camp stove, and it generates power for the family. It's just scaled up for family cooking. So buying the smaller camp stoves funds the distribution of the larger home stoves in need parts of the world.
Personally, I really like the idea of harnessing the power of capitalism to do good things for what Jesus called "the least of these".
“Hard times create strong men. Strong men create good times. Good times create weak men. And, weak men create hard times.”
― G. Michael Hopf, "Those Who Remain"
#TINVOWOOT