This is a 2-pack of Milwaukee’s 6.0Ah high-output batteries. These make a great alternative to a single 12.0Ah battery if you’re looking for a lighter weight battery (two of these are the same price as one 12.0Ah battery and both batteries are designated as High-Output by Milwaukee). HO batteries use the newer 21700 Li cells and have more power and run cooler than non HO batteries, which use the older 18650 Li cells.
I tested the batteries in several of my M18 tools, including a 2902 hammer drill, 2720 Sawzall, and 2730 circular saw. In every case the tools performed extremely well, meaning they exhibited a lot of power under load, and because of the battery’s weight, the tools were easier to handle than they were with the 12.0Ah battery installed. I also compared a “regular” 5.0Ah battery and the 6.0Ah HO battery using my Milwaukee 2902-20 hammer drill and a 1” auger bit (see Photos). I noted the temperature of each battery (using an IR thermometer) before and after drilling 20 holes in a pressure treated 4x6. While not a completely scientific comparison, I did note that the temperate after drilling was three degrees cooler with the 6.0 battery (72 versus 75 degrees, starting temperature for both was 60 degrees). When done, the 5.0 battery only lit 3 LEDs in its fuel gauge and the 6.0 battery still had 4 LEDs. I can’t draw too much of a conclusion from the temperatures (I think I would need to make many more holes to really compare them), but the runtime would be very impressive for the HO battery.
So, if you’re using Milwaukee’s high-demand power tools, you may want to look into the 6.0Ah batteries for easier handling than the 12.0Ah battery (of course, for the stationary tools, like the miter and table saws, the 12.0 would be just fine).
Good Size & Weight, Long-Lasting