Review on Power Up Your Tools: Get Waitley'S 2-Pack BL1850B-2 18V Replacement Batteries With LED Indicator by Marty Wainwright

As others have mentioned, the fit isn't perfect. I ended up getting an off-brand dual charger that it does fit well on, but the fit is hit and miss on several of my tools. The batteries do work on all of them, but on some the batteries don't lock, and on others I kind of have to force the batteries on. The life doesn't seem to be too bad, but not quite as good as the genuine Makitas. Overall a decent value, and not bad as a backup battery.