The seat is made of high-density polyethylene (HDPE) using a hollow blow molding process. The overall design of the seat is ergonomic to achieve a comfortable sitting feeling and reducesitting fatigue. The seat has superior mechanical performance, high strength, impact resistance, safety, good weather resistance, acid and alkali resistance, and antistatic. The seat design, shape and installation method meet the international general requirements,which are beautiful in appearance, comfortable to sit on, and easy to install, maintain and manage. Fixed grandstand seats can be divided into flat-mounted, side-mounted, and vertical-mounted seats with different installation methods, as well as integrated chairs and flap chairs, depending on the different needs of the venue.