Plant!T, 10 Liter, Horticultural Clay Pebbles, 8 mm-16 mm Pebble Size, Made From 100% Natural Clay, Are Clean, pH Stable & Offer Great Aeration & Drainage, Especially In Flood & Drain, Deep Water Culture & Drip Feed Systems, Due To Their Unique Structure & Ability To Cover A Large Surface Area, Offer The Ideal Environment To Foster Beneficial Bacterial Growth Around The Root Zone, Leading To Naturally Healthier Plants.