Box with 4 blades Second Nature's double edge (double-sided) blades are wafer-thin polished blades specially developed for our own Razor. These high-quality interchangeable blades are made of coated stainless steel with a non-stick coating so that the blade glides smoothly over the skin and are easy to install. A double edge blade has two cutting edges that you can both use to achieve a very smooth shave. Barbers don't use them for nothing. Note: these blades are unique and designed specifically for our razors.