Breathable waterproof garments are most likely to get sweaty and wet inside when used in damp or wet conditions. If the outer fabric absorbs water, the garment can lose up to 70% of its breathability. Therefore, the Durable Water Repellency (DWR) on the outer fabric of your jacket must be maintained to ensure comfort. Nikwax Tech Wash will revitalize the DWR and therefore breathability of your garment.