This is a European made reproduction of German WW2 set of 3 gas mask strap leather protectors. These leather pieces were put on the webbing straps to protect the strap from being worn from being rubbed on the metal bales of the gas mask can. Since the can is attached at 3 points there is a need for 3 of these leather pieces. See the attachment method in the pics and notice that the smooth side is the side in contact with the metal and lies between the metal bale and the strap. These were always made from the scraps of leather so they may have been colored or not, these have been blackened on one side.  It is $4.50 to ship this item anywhere in the US, Canada, Australia. NZ. and most of Asia and $4.00 within the EU.