 This is a randomized cross-over unblinded study in 30 subjects: ten with bronchiectasis and 20 with COPD with chronic bronchitis and chronic mucus production identified. Five subjects from the Bronchiectasis group and ten from the COPD group will start with oPEP and use for three weeks. All subjects will crossover at Visit Two after three weeks of oPEP therapy or three weeks of no therapy. Each subject will visit the centre on three occasions: Baseline, Crossover Visit, and Final Visit for approximately one hour each and will perform: 1 spirometry and plethysmography, 2 6MWT, and 3 health status evaluation using a self-administered SGRQ. Subjects will first provide written informed consent and will complete: 1 SGRQ after inhaling 2-4 puffs 200-400μg of the short-acting bronchodilator eg. Salbutamol, 2 plethysmography and spirometry 35 five minutes post-salbutamol. Vital signs will be documented and subjects will rest for approximately 15 minutes before the six-minute walk test 6MWT post-salbutamol. Subjects will be given an oPEP therapy system Aerobika to use at home, four times per day. Instruction and training on the use of the device will be given at the baseline visit. Subjects will be required to return the device upon completion of the study. 