Dyson V15s Detect Submarine Wet Dry Vacuum, Yellow/Nickel

It lights up fine dust and hair on hard floors, and it's the part of the machine that gets the most praise. The flip side, as one person points out, is that it also shows what the suction leaves behind. It sits on the soft optic head of the V15s, so it's a hard-floor tool.

It's mixed. For a quick pass after vacuuming it does the job in some homes. Others find it only freshens floors, leaves set-in grime behind and is fiddly to clean afterward. The wet roller works on sealed hard floors only, and clean and dirty water stay in separate tanks.

Often a whole floor. About 1,500 to 2,000 sq ft per charge is reported, depending on how dirty it is. The V15s is rated at up to 60 minutes, and higher power drains it faster. The screen shows remaining runtime, so the battery running down never comes as a surprise.

Yes. With heavy-shedding dogs and cats it picks up hair well on floors and furniture. One catch: hair still wraps around the small wheels on the floor head, so those need clearing on the V15s now and then.

It depends who you ask. A particle sensor counts and sizes debris and shows the totals on the LCD screen, and some find those dust counts interesting. Another person calls the readout useless once the dirt is gone. The same screen also shows remaining runtime, which is handy either way.

No. Dry vacuuming and wet mopping use separate cleaner heads, so you swap the Submarine head on for hard floors and use the dry heads on carpet, rugs and upholstery.