This is a video showing the drilling of live rock from a saltwater reef tank. The 1/2" holes are used for mounting pegs made from acrylic rods or other types of pegs or frag plugs. The live coral are attached to the end of the peg and can easily be positioned in the tank. This process also facilitates moving the coral to another location at a later time, they can be removed from the holes somewhat easily. It also prevents coral from falling as once its pegged well, its pretty much going to stay where you put it. No more snails knocking things down or balancing feats are needed.