These flat buttons were used for German uniforms during The First and Second world wars. They were sewn on camouflage blouses, shirts, pants (both cloth and HBT) and overalls of all kinds. In general this button is a classic, it can be used on any clothing.
Diameter 17 mm. Material: aluminium. Such buttons were produced untill 1940, later they were made of steel. Alu buttons may be washed along with clothes. They are durable, not afraid of washing and humidity.
Four-hole buttons were used usually on clothes, when three-hole mostly for equipment.