Valved holding chambers and spacers are very similar devices; both are plastic tubes that attach to your metered-dose inhaler and are recommended for adults and children. A spacer is a device that is placed on the mouthpiece of your quick relief inhaler. When used, a spacer creates space between your mouth and the medicine. This space helps the medicine break into smaller droplets. The smaller droplets can move easier and deeper into your lungs when you breathe in your medicine.