CaribSea is LifeRock Tree Extention Kit provides additional rock pieces and a support rod to add interesting features to your aquascape. Don't worry about having to drill or hammer your rock, CaribSea has taken care of the hard part. The Tree Extension Kit includes two hand-made arching rock pieces with naturally varying shapes, which are pre-drilled to accept the stabilizing rod which will hold everything in place. Once your dream rockscape is in place, you can secure the rock into a solid structure with the addition of some MarcoRocks Aquascaping Mortar.