CaribSea LifeRock LifeRock Ledges are the perfect building material for negative space aquascapes. These saucer sized flats are each uniquely made, not molded, so you will have variety in every box. These are perfect for simply stacking, or creating multi-level coral shelves by bonding with other LifeRock styles such as Original or Shapes. Like all LifeRock, Ledges are infused with living spored bacteria and NO CURING NEEDED! Perfect building material for negative space aquascapes Saucer sized flats are each uniquely made, not molded, for variety in every box Perfect for simply stacking, or creating multi-level coral shelves by bonding with other LifeRock styles such as Original or Shapes Infused with living spored bacteria NO CURING NEEDED