This is our small version of the Pavona Clavus cactus coral measuring 4.5x3x7.5 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 neon colors will glow under black light and most actinic led lights!! Thank You and enjoy! Call or email us anytime with any questions at 1-888-637-6598 or oceanaquaria@gmail.com