These Folios are built of our select natural Skirting Leather. They are assembled by hand with ABS plastic sheets as stiffeners in the leaves. We have improved the design to allow use of Top Bound Pads or conventional notebooks in either A4 or A5 sizes. The A4 size can be had with Pen Loops and Scale pocket for a truly unique piece of office or field equipment. We build these with a shallow scallop on the hinge line to avoid a common wear point. This is one more detail that builds value and long service into our products. We use this stuff and pay attention to details in construction and materials selection. All this returns more value and longer life in our products to you.