Inorganic & Sterile Growing Medium, great for Rooting Cuttings clone plants, germination start seeds and more. Encourages Faster Initial Rooting & Its Firmness Is Guaranteed | Much easier than starting in soil! Predrilled planting holes make seeding and plant propagation a breeze. Great for hobby and commecial growers | Provides 20% Air Space When Saturated - Absorbs nutrient solution while retaining plenty of oxygen for rapid root growth! | Made from good selection of natural rocks, neutral pH and sterile. Cubes Measure:1.5" x 1.5" x 1.5" | SELLER WARRANTY - Any support you need please email us via your order page, we'll respond to your request within 24 hours, and we promise 100% fund back if you do not like it, WHY NOT HAVE A TRY?