6 x 3 x 36 inch rockwool slab case of 12. Get the Grodan Expert Fat Slab to facilitate excellent final stage growth. Simply transplant your Gro-Block plant onto this slab just like professional growers! This product comes in clearly marked biodegradable UV resistant sleeves for comfortable handling and algae prevention. The benefit of using a Grodan Fat Slab is that roots are protected and contained for the life of the plant. This Expert Fat Slab also has vertical fibers for faster drainage; best for hobbyists. 15/75. 6 in x 3 in x 36 in.