Register for air conditioning

A register for air conditioning, comprising:

• a tubular retainer having opposite upper and lower walls and opposite side walls, the opposite upper and lower walls and opposite side walls forming an outlet opening and an air passage, wherein an opening surface of the outlet opening makes an acute angle with respect to a horizontal plane;
• a plurality of horizontal fins having a swing shaft, respectively, and disposed pivotally about the swing shaft within the retainer and arranged and spaced apart along the opening surface;
• a connecting rod for connecting the horizontal fins;
• an actuator for actuating the connecting rod to swing the horizontal fins synchronously with each other;
• and
• a movement structure for enabling the swing shaft of at least one of the horizontal fins to move back and forth with respect to the retainer depending on a swing angle of the horizontal fins with respect to a horizontal plane, wherein:
• the swing shaft of the at least one horizontal fin is moved back and forth by a horizontal back-and-forth distance,
• the horizontal back-and-forth distance varies according to a vertical distance between a bottom of the retainer and the at least one horizontal fin,
• the closer the at least one horizontal fin is to the bottom of the retainer, the greater the horizontal back-and-forth distance is.