These are ok I suppose, but they don't clean the board very easily; they drag on the board a bit and leave bits in the board. I like my classroom whiteboard bit-free so I've given them away and gone for the much much better Q Connect one, which wasn't much more expensive and which has several layers so will last a lot longer.
So, it mostly works - it does clean the board - but if you want magnetic, forget it. The magnetic quality is so weak that it does not stay on the board. Spend lots for something that doesn’t what it claims.