The OptiChamber Diamond valved holding chamber (VHC) is smaller than most conventional VHCs and incorporates a stepped mouthpiece, a clear, anti-static chamber, and a low resistance expiratory valve that helps measure breath count and breath hold. For use with inhaled steroids, as well as long-acting and rescue pressurized metered dose inhaler (pMDI) medications, OptiChamber Diamonds intuitive design enhances medication delivery and compliance for patients of all ages, at home or in the hospital.