Jar and lid are made of highly durable plastic Metal DISS female connectors for maximum strength and durability Ergonomically designed DISS connector is perfectly suited to connect to any flowmeter 6 mm flow nozzle for humidification or 22 mm ventilation hose connector for nebulization Dual functionality to convert the device from a nebulizer to humidifier Safety audible-alarm pressure relief valve sounds at over 2psi to warn patient and caregivers of obstruction of flow