Description Seal access points such as cracks, joints, seams and holes with MouseStop, and no rodents or pests will gain access. Once applied, the barrier is immediately active. The outer surface will harden smoothly but the inside remains soft. When rodents breach the hardened surface its soft inner core immediately deters them. MouseStop is instantly waterproof, a very important feature, the product cannot dissolve or soften when it comes in contact with water as the product would lose its effectiveness. MouseStop is composed of natural oils, fibers and fillers. Contains no pesticides or biocides making it a durable and environmentally friendly product.