Instruct: Classify the given Amazon review as either positive or negative.
Query: Best Peak Flow Meter I have tried

This meter is accurate in comparison to others I have tried and to "disposable" ones.I love it's ability to track previous readings as well as it calculating what percentage you are from your best peak flow. You can only compare your numbers to yourself so a peak flow of 380 could be good or bad, depending on what YOUR best peak flow is. This is really important and why I am glad it does its calculations automatically and easily displays for me whether I am in a danger zone for myself.This also has the ability to keep track of peak flows from different people but I am the only one in my house that uses it so I haven't tried that feature. There are different color mouthpieces for different people.