Oceans Wonders Coral Frag Tiles are perfect for the propagation or fragging of hard and soft branching corals such as Acropora, Birdsnest, Montipora, Kenya Trees, Xenia, ect. They are 3″ x 3″ and 5/16″ thick.  They are made from a fused special grade bright white reef sand. This sand is a natural calcium based sand which has been shown to speed the spread of coralline algae growth and corals on the tiles.