Hydrophane Leather Darkening Oil has a unique dual action formula. Firstly Hydrophane Leather Darkening Oil penetrates new leather and progressively darkens light colored leather. Secondly the unique oil formulation helps protect new leather and ensures that mud and sweat can be removed with cold water. Before using Hydrophane Leather Darkening Oil be certain that you wish to change the color of your leather. Although the product contains no dyes it is an irreversible process. Always test product on a sample of the leather that is not normally visible to confirm darkening effect. Leather is a natural material and Hydrophane Leather Darkening Oil may not be adsorbed uniformly in certain cases. This can cause slight non-uniformity of color.