Abstract: A register for an air duct is made up of extruded L-shaped members that have perpendicular integrally formed frame and duct inset parts locked in butting relationship at mitred ends by flat corner clips with resilient barbs that slip into and bitingly engage channels along the frame parts of adjacent members. End clips slip over the distal edges of the duct inset parts to secure the backs of adjoining members. Curved blades extend horizontally in louver fashion in front of pivotable vertical damper vanes across the register opening to provide airflow control.