The Heimplanet Fistral Groundsheet is a handy spare groundsheet perfect for protecting your tent from the cold and damage. The extra groundsheet provides protection from debris on the ground that may damage your tent and provides a layer of insulation to prevent heatloss. Hydrostatic head is a measure of how waterproof a fabric is. This is measured in millimetres to represent the maximum amount of water that can be placed on top of the fabric before water will begin to permeate. For example, a fabric with a hydrostatic head of 3000mm can withstand a vertical column of water up to three meters high. The higher the rating, the more waterproof the fabric is.
