Grodan 1.5" Rockwool Starter Plugs, 2 Sheets of 49 Plugs (98 Plugs Total) + Twin Canaries ChartBrand: Twin Canaries Liquid Volume Conversion Chart Features: Made from molten rock spun into cotton candy like fibers and then compressed into cubes, blocks, or slabs Has a tremendous capacity for absorbing nutrient solution while retaining plenty of oxygen for rapid plant growth Seedlings or cuttings started in the Grodan cubes can also be transplanted into more traditional planters and growing mediums Twin Canaries Chart included with every order!