The Mini-Wright was introduced in the 1970’s to enable the benefits of peak flow monitoring to be accessed in doctor’s surgeries and at patient’s homes, all around the world. It marked an important advance in asthma management because it enabled objective measurement of airway constriction and appropriate actions to be taken as a function of that constriction. Every Mini-Wright is individually assembled and calibrated by highly trained operatives to ensure consistent performance. All calibration test equipment is frequently checked to ensure that the highest of standards are met. Mini-Wright PFMs are manufactured to one of two standards; the EU and ATS Mini-Wright Standard is manufactured to one of two standards; ATS scale (tested to the American Thoracic Society standard) and an EU scale (tested to the European standard), colour coded for easy recognition. In addition a visually impaired version of the EU scale is available for those requiring larger numbers. The Mini-Wright Standard is fitted with an internal one-way valve; this avoids accidental inhalation through the device. This is especially important when the device is used in a multi-patient setting. For clinic use we strongly recommend the use of a disposable one-way valve mouthpiece to avoid cross-contamination.