*Update from original review below: 3 months later the device now randomly turns off and stays on for only a few seconds. The battery is fully charged and connected. A fully cleaned block and a removable square air filter inside it seemed to temporarily solve the problem, but not for long. The device still turns off after a few seconds. Removed the square air filter from the block and it worked fine for a few days and now shuts itself off again. Would love to try the new replacement air filter but Hoover doesn't offer them as you will see in other reviews. Now I'm waiting for a response from Hoover Warranty Support. It's been 3 months and it's already a big problem - I'm not impressed and won't be buying again! When my Black and Decker 16v cordless battery stopped charging I looked for a comparable device with a spare battery as the B&D model doesn't have one. The B&D unit was a great vacuum cleaner until it died and I found out that it's basically a disposable vacuum since they don't offer owners an easy way to change the battery. This led me to this Hoover vacuum with its universal battery pack that slides in and out of the unit. Problem solved! It's a little heavier than the B&D block, but not by much. The suction power of the Hoover is comparable to that of the B&D without the attachable extension. When I pull on the included extension (tucked under the Hoover unit for easy access) I notice a drop in suction which my old B&D didn't have when I extended it. Not sure why this is happening, but it happens. Still works well but with less suction power. This is my main reason for rating this device 4 stars instead of 5. I vacuum on average once a day for about 5 minutes (mainly pet hair, which is not a problem with this device). I noticed that after the second 5 minutes. session, the battery shows 2 bars with 4 remaining charge. When I start my third session, the vacuum typically shuts itself off after about a minute, so I've found my fully charged Hoover battery lasts about 11 minutes of full use. The removable battery charges fairly quickly and is easy to replace when it runs out. All in all a solid unit, especially if like me you're tired of buying disposable cordless vacuums that are going to go to landfill after the first year of use!