On respiratory out, the valve closes. Fantastic co-ordination is just not required. Spacers are not easy to use when out and about as These are fairly bulky - having said that all MDI bronchial asthma inhalers needs to be used through a spacer when in your house. Nebulizer: A nebulizer https://frigorifico-inaler-sa02332.designertoblog.com/58672988/frigorifico-inaler-sa-an-overview