The edge size coins to a machine with ridges and deep by round or so-called "edge gear" instead of a smooth edge. There main purpose is to prevent counterfeiting.
The coin's edge as a church deeply. As well as the surrounding Also known as "the wheel" rather than a smooth edge. The main aim is to prevent tampering.
The edge of a ridge coins machine size deep rate by round or called "the edge gear." instead of a smooth edges. The main purpose is to prevent forgery.