SMI Birch Flat Files. Beautiful Natural Birch Flat Files are made from natural birch plywood. Drawers are constructed exactly like the premium Oak Flat File drawers. Standard drawer pulls are almond colored plastic. White or black plastic drawer pulls are available upon request. Birch Files are excellent for the price conscious buyers who demand quality construction. Available in two sizes to hold 24 x 26 inch paper and 32 x 40 inch paper.