Castaldo LiquaCast Long Life No Shrink RTV Liquid Mold Rubber 1 kg / 2.2 lbs Package includes Part A & Part B can. Molds made of CASTALDO LiquaGlass liquid molding rubber will last many years if stored properly Exposure to moisture and humidity will tend to soften the molds and make them unusable For best results store finished molds in airtight containers such as the kind sold for food storage Do not store CASTALDO LiquaGlass molds in contact with molds made of the other types of rubbers