AAAA vs. D Battery
Comparing 2 standards across 6 specifications. 6 key differences identified.
A AAAA battery (IEC designation LR8D425) is a 1.5V Alkaline cell measuring approximately 8.3mm in diameter and 42.5mm in length -- smaller than a AAA. It's used in devices with especially tight internal space, such as laser pointers, some styluses, and compact LED penlights.
A D battery (IEC designation LR20, ANSI 13A) measures 34.2mm in diameter and 61.5mm in length -- the largest common cylindrical primary cell. Alkaline D cells output 1.5V nominal, with typical capacity in the range of roughly 12,000 to 20,000 mAh depending on discharge rate.