Cultilene has many years of experience developing Rockwool products in the Netherlands and is preferred by some of the largest industrial propagators in the world. The quality of their newest Rockwool cubes, plugs, and starter sheets is by far the best on the market with superb air to water ratio and a fibre structure that holds water longer and has less resistance for the roots to grow in, resulting in stronger roots. Cultilene Rockwool also encourages faster initial rooting and its firmness is guaranteed. Grow Cubes are 1/2X, cubes of Rockwool which can be mixed with other loose media. Sold by the case.