How does an inhaler work? And why is there a brown inhaler and a blue one? What is the difference?

Question: How does an inhaler work? And why is there a brown inhaler and a blue one? What is the difference?
- Keywords:
  blue,
  brown,
  inhaler
Asked by KMB to Lucy, Miranda, Peter on 17 Nov 2016.
- Miranda Bane answered on 17 Nov 2016:
  
  An inhaler contains chemicals that relax muscles. When you use an inhaler the chemicals go down into your lungs and make them relax so you can breathe easily. I think the blue and brown just show that they are difference chemicals that are different strengths depending on how much you need.

Question: How does an inhaler work? And why is there a brown inhaler and a blue one? What is the difference?