Breather Mask Question(Not a question about where to buy one.)

Today I received my simpson breather mask from Brendan Murray, and on the inside of the mask where the respirator meets the cotton there are four male end of snaps, one on each corner if you where to draw an invisible square. Does anyone know why those are there? There is no female end to the snap, that I can see anyway. Thank you.
Randy

 

they are for the straps that originally came on the resperator ,I have a box full of them if you want some -Brendan