One reviewer says their vacuum now runs “almost twice as long” thanks to this simple upgrade.

The notice prompted Chief Financial Officer and the State Fire Marshal Jimmy Patronis to warn consumers against purchasing Amazon’s lithium-ion replacement battery packs for Dyson vacuum cleaners.

If something runs on batteries, you’ll find a battery meter somewhere on it. Your smartphone, your vape; even batteries themselves can tell you how close they are to dying. So why am I excited about ...