I always preferred cello anchors that are just a round rubber or plastic circle, not attached to the chair. However, there are times when you have to be absolutely 100% sure that the spike is not going to move unexpectedly together with such an anchor. Most cellist in my amateur orchestra have exactly this model and are very happy with it. So am I: it can accommodate chairs even with "fat" legs, it has a rubber bottom, so it doesn't slip on the floor, and it will work for both "pointy" and "stubby" endpins (so there is no need to take off the rubber end, if your cello has one). The only potential issue is the length of the strap, for some people it might be a bit short. Personally, I have to use it almost at the full length.
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