What temperature can these devices reach? Edit: I found as low as 11 deg Celsius http://www.lifehacker.com.au/2013/01/make-an-electricity-free-zeer-pot-fridge-t

What temperature can these devices reach? Edit: I found as low as 11 deg Celsius http://www.lifehacker.com.au/2013/01/make-an-electricity-free-zeer-pot-fridge-to-keep-your-drinks-and-food-cool-in-the-sun/ http://www.lifehacker.com.au/2013/01/make-an-electricity-fre...