They are referred to as the Beta button, button shirt.
Pronged Snap Fastentrs traditionally consist of 4 parts
and by design are a big brother shirt buttons
The main diameters of the buttons:

The shape of the face of the button predominantly round. Flat surface, without any frills.

But many clothing manufacturers put on their buttons logos.
    

The crown part of the button is of two kinds

   
But, unfortunately, for more details on the crown button on the strength is not affected.

The types of materials and coatings

Kamarnya buttons differ not only in material, but also put on them to the floor:

• metal, stainless steel, uncoated. A possible way of processing - polishing;

• brass ring, without coating. As the surface treatment used chemical passivation;

• copper uncoated. As the surface treatment used chemical passivation;

• steel bracket with plated.

Main color buttons: Nickel, black Nickel oxide (black), antique (bronze), bosmina color enamel in a variety of colors.

(Can be painted by yourself using nail Polish).

The use of both proprietary nozzles - punches

Device - punches - matrix for this type buttons (made in Turkey)

заменить на индекс А
                      
       
                       
 

Device (nozzles) production of Greece: