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The highest rated waterproof hiking shoe models (page 7)

Waterproof fabrics provide the highest level of protection against liquids. Within waterproofing, there is a range of ratings from 5,000mm (not very waterproof) to 20,000mm+ (will withstand just about anything). Although fabrics can be fully waterproof, with enough wear, pressure and water, they will eventually leak. Breathability should also be considered when deciding on the waterproof level as the fabric may keep water out well but you’ll end up wet if your perspiration can’t get out.