Cultiwool 6" x 6" x 4" Blocks of Cultilene Rockwool with Optidrain - Case of 64Description Unique Cultiwool Growing Blocks: Cultiwools growing blocks are efficient in a distinctive manner. They possess a consistent quality that allows for a quick and homogeneous distribution of water throughout the substrate. This trait is among the most crucial for an effective growing medium. Highest Quality Stone Wool: Expect the finest stone wool in the market with Cultiwool. This brand is the first to introduce the donut ring for the retail