The blue fitting is Φ33, and the black one is Φ37 (internal diameter).
For mine, it's small so I use it with a workaround, but on the vacuum cleaner it fits perfectly and does an amazing job in the car.
At home, apart from the shutter/window rails and maybe a keyboard, I haven't used it anywhere else.
-1* because it could have had a "rubber" adapter to fit "all" vacuums

It does what it is intended for but I remove one star because in bosch gl-30 with f35 hose if I am not mistaken, it does not fit even though it says universal.
Health.

It does the job. The tubes suck up the dust without scratching. It fits into the vacuum cleaner with the appropriate adapter.

For crumbs and very small objects, yes, but don't think that it will replace the other components, think of it as an extra

I didn't expect to use it immediately. I just bought it to have it as an accessory for the vacuum cleaner. In the end, it has many more uses than one would think or advertise. We even managed to remove a screw from the TV that wouldn't come out even with a magnetic tip.

Despite claiming to be suitable for all vacuum cleaners, including mine (Miele), it does not fit well. However, it still gets the job done

So far, I have used it 2 times, but it does exactly what it advertises! Very good and smart accessory. Worth buying

You can remove the dust from inside the drawers without taking out the objects, because there is no fear of the vacuum sucking them up

Necessary accessory for household cleaning! It fits everywhere. I bought it to clean the joints of aluminum and under refrigerators and washing machines. It easily fits all types of brooms, even stick ones. I definitely recommend it!

Very convenient accessory, you can remove the dust from the inside of the drawers without first emptying it from small objects, because there is no longer fear of the vacuum cleaner sucking them up! Also inside the radiator body, on the computer keyboard, on the shelves where many small objects are gathered, in jewelry cases, etc.