Hard corals are generally broken down into two categories; Large Polyp Stony (LPS) Corals and Small Polyp Stony (SPS) Corals.
The LPS Corals are generally larger calcareous corals. They have much larger fleshy polyps than those of the Small Polyp Stony (SPS) Corals.
Many LPS Corals are quite hardy and can even be fast-growing. These Stony Corals are generally easier to keep in the aquarium than the Small Polyp Stony (SPS) Corals.
For the most part, they require less intense lighting and a lower water movement than SPS Corals.