Sri Lankan pepper grows on vines trained up shade trees in the wet hill country. The berries are picked as they begin to turn, then dried in the sun until the skin wrinkles and blackens.
It is known in the trade for a high piperine content, which is the compound behind pepper's heat, and for an unusually floral aroma that survives drying. Both are why Sri Lankan pepper sells at a premium against the higher volume origins.
Every batch is hand-sorted before packing to pull out light and broken berries, so what reaches your grinder is uniform and grinds evenly instead of jamming.
If you have only ever used pre-ground pepper, this is the single easiest upgrade in any kitchen. The aroma from freshly cracked peppercorns is gone within minutes of grinding, which is why the pre-ground version tastes mostly of dust.