Compared to soil, the plant nursery block is much easier to pre-plant.. Sowing and propagation of plants becomes a breeze.. It is very suitable for hobby and commercial growers. rockwool starter have an enormous ability to absorb nutrients, while retaining enough oxygen to promote rapid plant growthRockwool grow pad is made of marshmallow-like fibers made from rock that is melted down and then compressed in a cube and treated with high temperature, which is non-toxic and harmless Rock wool screwdriver caps have low bulk density, light texture and high porosity. Good air permeability, strong absorption of water, good drainage, very suitable for rooting and cutting clonal plants, sprouting initial seeds, etc. The size of hydroponic grow cubes is suitable for standard flat planting tray, which suitable for cultivation and colonization of various plants Note: The data is all manual measurement, please allow 1 - 3cm error, due to the difference in light and display , there will be a certain color difference, depending on the physical object received.