I have purchased one gross (144) of thick MOP shirt buttons from the following source (mentioned in a recent thread on the topic): http://www.hst.com.sg/acatalog/Mothe...l_Buttons.html The buttons are the "Queen of Mother of Pearl" (T2310) ones (third button down in the listing) and are about 10 mm. (.40") in diameter (referred to as "16 ligne") and, by my measurement, about 3.55 mm. or .140" thick. This is very thick for MOP. As a comparison, the super-thick Borrelli shirt buttons are 3.95 mm. thick, just a little thicker. These buttons are really beautiful--quite luminous and showing the typical MOP colors. This was a group purchase, but I do have a few left over if anyone is interested. The cost is $1.59 per button (what I paid by buying a gross--$229 US for 144 buttons), and I can cover shipping to Canada or the US. Let me know by PM is you'd like a few for a custom shirt project. You need 7 for a shirt with no gauntlet button and French cuffs; 9 for no gauntlet button, but one-button cuffs, and 11 for two-button cuffs or one-button cuffs and a gauntlet button.