Our ballast rock, also known as ‘ballast 4’ is a material created from lime rock. This material is amazing for providing stability while also allowing smooth drainage. It can also be used for entrances and exits to job sites that use machinery with large equipment. These rocks are 1 inch in size. It can also be used for drainage, not ideal to walk on it barefoot, properly cleaned gravel offers excellent drainage facilities, well packed gravel req. less maintenance and has great durability.