3cm is a standard thickness for stone, which equals 1 1/4″ thick. Another common thickness is 2cm, or 3/4″ thick. These are the typical edges that you can get for standard thickness stones.
These edges are two slabs of stones glued together to make a thicker appearance, often 2 1/2″ thick. You can take any combination of single thickness edges and put them together for a great finish.
A stop-router is what we call when an edge dead-ends into a wall or cabinet. We “stop the router” from edging to make the edge square. This is a much better look with backsplash and tile. Here are some examples.