HandleHandle converts into a carrying case for ultimate portability and protection.ZonesBuilt-in flexible three-zone management system and easy-to-read numbers. The integrated three-zone asthma management system helps patients comply with treatment regimens. The color-coded indicators (located to the right of the scale) can be adjusted to delineate a patient"s green, yellow, and red zones based on personal best peak flow.RangesAvailable in Full (60-810 L/min) and Low (50-390 L/min) ranges.MouthpieceSafety mouthpieces reduce the risk of cross-contamination during multi-patient screening, and the one-way valve prevents patients from inadvertently breathing in air through their meters during peak expiratory flow rate testing. Life SpanAccuracy and reproducibility assured for a minimum of two years. Quality Assurance100% of Personal Best units are quality-control inspected at the factory before shipment.WarrantyPersonal Best® is backed by a one-year unconditional warranty. Any unit performing unsatisfactorily for any reason during this period will be replaced free of charge by Respironics.