Rockwool cubes - large x 24

This advert is for a tray of 24 cubes 

Rockwool is made from molten rock spun into cotton candy-like fibers and then compressed into cubes, blocks, or slabs.  Rockwool cubes effectively absorb nutrients getting your plants off to the best start. Seedlings started in cubes are easily transferred.  Seedlings or cuttings started in cubes can be transplanted into more traditional planters and growing mediums.