Laerdal® Pocket Mask® - the most widely used CPR mask in the world! The Laerdal Pocket Mask is especially designed to be used by the professional rescuer and first responder. The Laerdal Pocket Mask combines a low resistance one-way valve with a disposable hydrophobic filter to help prevent the passage of liquids and secretions. An optional oxygen inlet facilitates delivery of supplemental oxygen during ventilation of a non-breathing patient or for inhalation by a spontaneously breathing patient.