AAA Lithium Batteries.
For the Altiron altimeter from Parasport Italia and the original GoPro HERO wide.
Energizer® Ultimate Lithium AAA batteries help the Altitron as well as the standard definition GoPro cameras function longer, operate and perform better, and keep running even in cold temperatures. They are also 1/3 lighter than an alkaline battery – great for when weight is important.
* 4 AAA Lithium Batteries