#1 In most areas of the country , no state or local law require you to buy a container to surround the casket in the grave. However many cemeteries require that you have such a container in order to maintain the grave. Either a burial vault or a grave liner will satisfy these requirements. #2 The descriptions "Protective" or "Airtight" are the manufacturers'. Neither the funeral home nor any of its employees represents or implies that any vault will be air-tight or will provide long-term preservation of human remains.