Nitro cards are used as a seal between the powder and the shot. They can be used in place of a plastic shotcup in European-style loads. Modern load designs use nitro card wads within a shotcup for managing space. Nitro card wads are constructed of a specilized material selected to withstand the tortures of slow-burning powders and heavy payloads. (.070-.080" thick / .815" diameter) Good for 10ga thin wall brass hulls.