Repeated soaking and drying of leather can damage the fibers, causing boots to become stiff and eventually ruin the snug fit. Danner Waterproofing Gel blocks water from the outside without compromising breathability. Boots with a GORE-TEX liner are waterproof, but treating the leather is important in order to prevent the creation of water spots between the leather and the GORE-TEX liner. We do not recommend using Danner Waterproofing Gel on nubuck, suede or rough-out leathers as it will darken the color.