Grodan Delta 4 Block, 3" x 3" x 2.5" with hole, case of 384 RWDM4G | Grodan

Grodan Stonewool (rockwool) is made from molten rock spun into cotton candy-like fibers and then compressed into cubes, blocks, or slabs. Where other rockwool brand manufacturers cut all sizes from one batch of wool, Grodan is unique by making differen