Generally is fabric surface with a layer of coating, to let the water won't easily penetrate in cloth, usually in the cloth cover forming droplets (such as lotus leaf). But not really waterproof, water retention time long will ooze inside. The fabrics of W/R processing will fail because of washing and use for a long time, even if Gore - Tex W/R, some are more durable than ordinary W/R.
General vamp can use waterproofing agent. Waterproofing agent is efficient infiltration waterproofing agent, silane molecules through the surface infiltration base material, react with water molecules and acid and alkali substances generated on the surface of the deep group. Groups and base material form the waterproof layer, effectively restrain substrate ooze water, get damp, and could make up for a small fracture and permeability. Keep the original appearance. Uv resistance, freezing resistance, high temperature resistant, excellent resistance to chloride ions, acid and alkali resistant ability, repelling water effect significantly for a long time. Unique single permeability, and can make up for the 0.2 mm gap.