I just acquired Canadian military wind overpants. They are a cotton-nylon blend wind overpants dating back to October 1972 with the Nato stock number. A funny detail caught my attention, the way the buttons are attached to the fabric:



I did a quick google search and found a name for them: Canadian style slotted buttons. They look so much sturdier than normal buttons and seem to be easier to repair in the field. It also looks like they may be a good alternative to metal bachelor buttons for button suspenders on thinner pants:



It happens to have been introduced during the 50s by the Canadian army.

Can I find these types of buttons in normal sewing shops or would I have better chances in army surplus stores?