Mantis Bio Frag Plugs
Due to the extremely porous nature of the Bio Frag-Plugs, water current can penetrate the Bio-Plug to reach the surface of the coral frag, both from the top and bottom, this allows the coral frags to extract nutrient from the water column easier.

The Bio Frag-Plugs also serves as a bio-media, huge amount of bacteria colonies grow inside and on the surface of the plug, many of which can be easily captured by the coral frag polyps as food, which further increases growth rate of coral frags.