The present invention relates to a mask (16) for positive airway pressure therapy comprising: a mask cushion (19) configured to sealingly engage a patient's face； a mask frame (17) that forms a chamber with the mask cushion (19)； headgear that is attachable to the forehead support (10) and the mask frame (17)； and a forehead support (10) extending from the mask frame (10) and being adapted to be movable between a first position with respect to the mask frame (17) and a second position with respect to the mask frame (17), the forehead support (10) comprising:a biasing mechanism (42) that urges the forehead support (10) toward the second position；a cushion frame (12) including a shaft (40)；a frame extension cylinder (30) provided above the mask frame (17), the frame extension cylinder (30) including a bore (36) that receives the shaft (40) and the biasing mechanism (42)； anda radial projection (38) and radial groove (44) configuration that ensures the cushion frame (12) and the frame extension cylinder (30) are properly aligned andwherein the biasing mechanism (42) biases the shaft (40) away from the frame extension cylinder (30).
