Boundly conventional square aluminum ceiling can be divided into two kinds . Ther are high edge right angle and short side right angle . High edge has a length of 27 mm, using the keel installation can make sure the structure flatness and steady. Short side has a length of 18 mm, using triangle keel installation can make sure the structure flatness, firm and integral plane has good effect. What' more , beautiful smooth lines without the advantages of interior decorating. The characteristics of convenient installation, they are liked deeply by widely customers. These can be used in courtyard, school, dust-free space , etc.