FK-10 type air square casual flow, air flow type genus attached (flat delivery) type. Apply studio, hospitals, theaters, classrooms, concert halls, FIG Wei hall, recreation hall, theater lounge, general offices, shops, hotels, restaurants and gymnasium. To enable people to avoid interference noise and discomfort in a variety of environments, in addition to the neck according to the performance table to determine the wind speed, the need to consider the installation height and installation applications. FK-31 type tuyere is evolved on the basis of the FK-10, the difference: FK-10 is square, FK-31 is rectangular, substantially the same structure.