These buttons are special because the rim is lower than the buttons middle section. Mostly that is the other way around. The brown, beige, light grey colours are mixed well but every button is different. Brown is the main colour. This is a buttons suitable for jackets and (over) coats. The cross section is 34mm and there are also smaller ones of 25mm
Easy to sew on with the 2 holes

Colours on the colour chart of Seralon universal sewingthread by Amann Group Mettler
Brown - 324 - 1183
Grey - 3525
There are more browns in this button but these two give a good indication of the shades of brown present