A spacer is a tube or chamber that attaches to a metered-dose inhaler to make it easier and more effective to use. It holds the medicine in a mist, allowing the user to inhale it slowly and completely, which increases the amount of medication that reaches the lungs and reduces oral side effects. Spacers are particularly useful for people who have difficulty coordinating their breath with the inhaler's spray, such as young children or those with poor "hand-lung coordination".