I am pretty familiar with all the online purveryors of buttons. Last one I corresponded with went like this: Me: Your #XYZ button - is it pearl or troca? They: What is troca? The 3.2 mm Gritti buttons are what I use in 16 and 18 ligne (that is 3/8" and 1/2" respectively. You can see them in closeup on that blue Italian collared shirt in the linen shirt thread. 18 on cuffs and 16 on sleeve placket in the lower photo. I haven't bought in a few months since the dollar took its latest dive, but they are about a buck each. I don't mind selling them if you know size and how many. Just PM me if you really want them and I'll check the latest price. I do not use the 4.0mm "Borelli" buttons, so if that is what you seek you are out of luck. I don't like their proportions as I consider them too thick for the small width.