Other HVAC equipments cover a variety of auxiliary devices designed to complete the HVAC system. These devices have diverse materials. For example, metal ventilation ducts have good strength and air - tightness, while plastic air vents come in various shapes and are corrosion - resistant. Their advantages are obvious. Ventilation ducts can efficiently transport air, and air vents can flexibly adjust the air direction and volume. Widely used in HVAC systems of various buildings, they work in coordination with the main equipment to optimize air circulation, improve the overall performance of the system, create a comfortable indoor environment for people, and meet the personalized needs of different places.