Grodan Pargro Quick Drain Stonewool Slab 6 by 36 Inch, Case of 12 Made at the Grodan factories Plain brown half case sizes Better quality and drainage than other value-priced Rockwool Resting saturation measurements taken from QD slabs vs. Neptune slabs. Pargro QD was 10% drier than Neptune slabs Plain brown half case sizes. Better quality and drainage than other value-priced rockwool.