The Chile de árbol is a small and potent Mexican chili pepper also known as bird's beak chile and rat's tail chile. These chilis are about 5 to 7.5 cm long, and 0.65 to 1 cm in diameter. Their heat index is between 15,000 - 30,000 Scoville units. The peppers start out green and turn a bright red color as they mature.
