This carefully crafted Riverbed substrate composition recreates the unique features of high mountain rivers and streams, where rock shale and rubble are worn by the water into smooth cool pebbles. The Ibon River Kit includes a variety of sizes of our Black Venom Boulders, whose dark, solid forms offer a bold presence within the display. The kit also contains light sand blended with small dark smooth stones, providing a high-contrast mix of textures and colors.