This is our small barnacle cluster coral measuring 4.5x3.5x3 inches high. These are made of a durable, flexible and nearly unbreakable UV stable polyurethane composite safe for all aquariums. Many colors to choose from.  All of the neon color options will glow under black light and actinic led lights!! Thank You and enjoy! Call or email us anytime with any questions at 1-888-637-6598 or oceanaquaria@gmail.com