Abstract: This invention provides a headgear for a mask assembly including straps for positioning on the head and means to minimise deviation from an optimal mask assembly setting when engaging or disengaging the mask assembly from operative use. Preferably, the disengaging means is a variable-length strap incorporating at least one length delimiter, which may be a hub in the strap or an alternative means which employ friction to remain in place. The strap surfaces may be modified to provide the delimiting means. The strap may incorporate a second delimiting means in moveable engagement with the strap. Preferably, one engagement means is in fixed engagement with the strap. One delimiting means may be a thickened strap portion. However, other means for delimiting the effective strap length may be used.

Abstract: TThe present invention provides a water reservoir for humidification of the gas delivered by a gas-delivery device. The water reservoir comprises of a container having at least one opening for gas movement, and a means to prevent water escape through the aperture while allowing passage of gas to be humidified and delivered to a subject. Preferably the means to prevent water escape is a baffle. Preferably the baffle is disposed opposite at least a portion of the opening. The baffle may be continuous with a wall of the container. The container may be comprised of a deformable material.