Grodan Rockwool Grow Cubes (Mm 40/40) 25 Cube Sheet - 1.5 x 1.5 x 1.5 Inches These are individually wrapped small cubes for seeds and cuttings Rockwool cubes guide roots downward You can set them on top of other rockwool cubes, slabs or other growing media Sold in packls of 25 cubes Measure MM 40 / 40 1.5 x 1.5 x 1.5 inches