Holding Chamber OptiChamber Diamond, 10/pack.Low resistance inspiratory and expiratory valves open freely, even under low pediatric pressures and flows.Soft-seal technology is designed to contour to face, reduce leakage with minimal applied force.Uniquely designed stepped mouthpiece facilitates transfer from pediatric mask to mouthpiece.Clear, anti-static chamber delivers consistent aerosol therapy and is ready to use right out of the package.