To be certain that a message (or, say, a duplicate of Urbex) still left in a drain will final for a prolonged, very long time, roll the product up and insert it into a cleanse, perfectly dried 1.25L PETE drink bottle. Long, 38 inch (965mm) boards are additional comfortable to lie on but fewer likely to be ready to be turned all over in a offered drain (need a 1050mm diameter pipe to turn in) .