A search for “2AA” turns up a lot of discussions along this line.
https://www.google.com/search?q=site%3Abudgetlightforum.com+AAA+AA&client=firefox-b-1-d&ei=aXloYrKPG8jGkPIPjoSfsAQ&ved=0ahUKEwjy5-S06rL3AhVII0QIHQ7CB0YQ4dUDCA0&oq=site%3Abudgetlightforum.com+AAA+AA&gs_lcp=Cgdnd3Mtd2l6EAxKBAhBGAFKBAhGGABQ4Q9Y4Q9gvR5oAXAAeACAAV2IAV2SAQExmAEAoAEBwAEB&sclient=gws-wiz
Just one example: Best 2AA light out there