Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: What's the diameter of the charging base/stand?
Document: the second button is a slider that powers on the unit on or off.engage the pivoting nozzle until it is against the unit's body to make it compact and ready for its charging base. the powered charging base's plastic seems flimsy compared to the vacuum's heavy duty plastic, but it's sufficient to cradle the vacuum for charging.
It holds a fair amount of dirt/dust and does a good job. The price is reasonable and a fair value, I think, for the quality you are getting.The charging stand is very light and easily moves if you tug the cord (when the vac is not in it), I wish it were a bit heavier, but this is a minor thing.
The charging base is great too, nice and sturdy (comes with screws to mount if needed).The pivot head is great for many surface areas like the top of a shelf or ceiling fan blades because you can angle it just right. Another major feature of this model is that you can wash the filter and filter cup/bowl to get the dust out and clean it real good. You can purchase replacements if needed for just under $8.
I never thought I would give a hand vacuum five stars, but this deserves it.Compact:  The nozzle folds down so the vacuum is very compact when charging.Charger:  It comes with a charging base. The vacuum sits on top of the base and a blue light blinks while charging. Although the instructions say to charge for 24 hours, the light stopped blinking after two hours. I left it charging for 18 hours before using it for the first time.
My original pivot vac will no longer keep a charge, and I've been looking for a decent replacement. Thank goodness that B&D; finally came out with this lithium powered model! It has the rubber flap to keep debris from falling back out, and a charging stand that automatically makes contact and can be wall mounted. It is more powerful, runs much longer, all while being smaller & lighter. The brush pivots up when needed and is never lost.
Wow, this is like the Porsche of handheld vacs - this thing not only does a good job, it looks good doing it - AND it sounds like a tiny jet engine when it starts up. Love that they FINALLY added a charging stand for this updated model, first one we bought (and still use) had no charging stand - so nice upgrade. If I could afford it I'd buy one for every room - very good quality for a B&D tool.
Had the previous 18 volt model and it worked pretty well until I tried to clean up plaster dust from working with drywall. The fine powdery stuff choked it and motor burned out. So I got this bigger and newer model. The motor take a second to wind up to full speed, something I did not expect. But it is powerful and efficient. Runs much longer without losing suction. I especially like the handy charging stand to store it when not in use.
Good suction - things go in and stay in - excellent battery life, easy to clean and empty. Charging stand/cradle made of flimsy lightweight plastic, so definitely use the provided screws to secure it in place. The design on the Black and Decker Max Pivot is pretty awesome, very easy to use to access awkward places, and the built in tool in the nozzle pulls out to narrow the suction for smaller areas. It folds in on itself to charge, has minimal space requirements to store. Overall A.
This vacuum does what I needed, picking up small messes. The base is a little flimsy but is okay. I would recommend it.
Seems to have pretty good power, battery lacks a little in longevity. Hopefully it will stand the test of time.
Answer: L:5 1/4" H:3.5" W:5" The charging base is mountable.