As all other Brusso products I've bought, these ball catches come to very high accuracy and precision.
Installing them called for quite some care. They are tiny, need precise alignment, and quite exact positioning. The installation leaflet by Brusso was very helpful, but I am glad doing a few tests.
These ball catches come in imperial dimensions. After testing with metric drill bits, I think one is well served using a 1/4".
I am very happy with how they are next to invisible, allow for smooth opening and closing of the doors of the cabinet they are installed in, yet keep the doors closed.
Due to properties of wood to not always stay completely flat, I think I will in future projects use two sets of these ball catches per door.