6” x 6” x 4” Cultilene Rockwool Cubes (64pk)The cultilene rockwool cubes are composed of a fibre structure with the perfect amount of water and air to boost plant growth while forming healthier and thicker roots. The cubes feature an opti drain design with cross shaped grooves that help get rid of the excess water, so plants grow healthier. The fibre provides low resistance, which helps the plant grow stronger roots. Healthy Roots: Due to the very little resistance offered by the fibre, the