The Prestonett Waterproof Masonry Filler is a 5kg grey product suitable for both interior and exterior use. This masonry filler is designed to provide a reliable and durable solution for repairing walls and surfaces. Its waterproof properties make it ideal for both wet and dry conditions, ensuring a long-lasting and effective result. Whether you're looking to fix cracks or smooth out rough surfaces, this filler is the perfect choice for all your DIY projects.