Around 80% of the natural bird's nests harvested from caves are eliminated due to its quality. Only 20% of natural bird's nests can be clean by handpicked. Among the 20% of the bird’s nest, only 6% of the bird’s nest is heavier than 12 grams. It is rich in nutrient, aromatic, and tastes excellent. These bird's nests were used to paid tribute to the emperor before, and they were called Authentic Bird’s Nest.