Milwaukee 48-11-2422 M12 battery

Voltage identifies the battery platform. Some makers quote a peak (max) figure at the start of discharge while others quote nominal, so 18 V nominal and 20 V max packs usually have the same cell count. Higher-voltage platforms typically serve more demanding tools. Batteries only fit tools from the matching line.

Amp-hours (Ah) is the battery's charge capacity. At the same voltage, a higher Ah pack runs longer between charges but is usually larger and heavier. Smaller packs keep the tool lighter for overhead and light work; larger packs suit saws, grinders and other high-draw tools.

Battery weight is the pack on its own, as listed by the maker. Add it to the tool-only weight to estimate the working weight. Higher-capacity packs add weight, which you will notice in overhead and all-day work.

A charge indicator shows remaining charge, usually as a row of LEDs on the pack or charger. It is a rough guide, not an exact percentage, and readings can shift once the battery rests or cools. Some chargers also show fault or temperature status.

Battery line is the maker's platform name, which determines which tools and chargers the pack fits. Makers generally keep one battery design across a platform, but batteries from different makers are not interchangeable. Buying into a line is often a longer-term choice than buying a single tool.

This is the maker's published warranty term. Terms for tools, batteries and chargers often differ, and some depend on registration or exclude certain uses. Read the maker's terms for what is covered, how claims are handled and whether proof of purchase is required.