4” x 4” x 4” Cultilene Rockwool Cubes (144pk)Encourage the growth of healthier plants and roots with the cultilene rockwool cubes. With the natural ability of the rock fiber to withhold air and water in proportion. Also, the rock creates very little resistance, which encourages faster rooting and a firm root structure. The rockwool cubes measure 4 x 4 x 4, and the grooves are cross shaped, which makes excess water runoff while maintaining aeration and stimulation of root growth. Faster Initial