I will agree that the rubber base does not fit well and when water collects, it splashes everywhere due to the back and forth motion during grinding.

As for the stones, I sharpened 7 knives that I had at home (chef, santoku, boning, and 4 general use knives), and because you correct with the 400 grit stone, it has worn down so much and so quickly that to bring it back to its normal state, it needs to be half its size. Yes, the knives became so sharp that they can slice thin sheets of paper like the videos on YouTube, but it's a shame that the stone wore down so quickly. You get what you pay for. I bought the stones on sale for 48 euros.

I should note that while I had watched a bunch of videos on the correct sharpening technique, theory is one thing and practice is another. Of course, now that the knives are in good condition, the 400 grit stone is no longer needed and you can make them very sharp again with the 1000 and 6000 grit stones. Perhaps a higher quality stone with lower grit may be needed to be able to correct with it without it wearing down so quickly.

Useful tool but unfortunately the rubber base does not adhere well to the wooden surface and needs something to stabilize it (e.g. a coin). There is no such issue with the corresponding 400/1000