Growing up I remember going to the doctors with my sister who has asthma and her blowing into her peek flow to measure how much she could exhale. She then brought her peek flow home and got to write the answers down each day and make a pretty little graph with the results. Obviously I couldn''t resist having a go on the peek flow also even though I do not have asthma. I found it really hard as first but there is a knack to it. One really big breathe and the fill your cheeks up as you blow out to get the best and highest result. I don''t think that I ever really got the technique right though as my asthmatic sister always seemed to get a higher result thasn me unless she was really poorly. My husband and brother in law also suffer from asthma and apparently as kids they would have competitions with their peek flow meter which I guess is a good way for kids not to feel so bad about having asthma, and a good way for kids to have some fun with it. The peek flow meter is always white plastic with a red meter reader. It is used to measure lung capacity and how good or bad a person is doing at breathing. I''m sure most people would be able to just say how their breathing is but this makes it more scientific and doctors cans really gauge results of using the different inhalers that are prescribed and monitor how patients are day to day.