Started out as all linen with green liners (red liners indicated special projects).
Then the tan line came out and the linen looked terrible on them so they went with canvas on those.
Then Tony talked Jeff and Mike into that hideous orange and green monstrosity.
Then, the 3mil was clothed in canvas as to make it differ from the standard 3 series.
And finally, the 5 and hoongl-ass were born and wrapped in that fine looking canvas.