Inclusion Criteria:  Infants and children with CF under the age of 6 and their parent/guardian/caregiver to perform chest percussions using percussor palm cups. Participants must currently require regular chest physiotherapy.  Exclusion Criteria:  A comorbid condition that is a contraindication for the use of percussor palm cups. Inability of parent/guardian/caregiver to complete written questionnaires due to visual or cognitive impairment.