Cultilene 4 x 4 x 4 Case of 144 Blocks have an optimum air/water ratio. Allowing for healthy root growth and great continued rooting thanks to the extremely even distribution of water and EC. These blocks have an excellent water absorption and (re)saturation rate. Plus feature the exclusive Plant Comfort fibre structure which has a lower density of resistance during rooting with no loss of firmness. All blocks except the 3x3x3 also have the Optiplus feature, which is a unique design on the underside of the block allowing for excess water to drain away easily.