Medical Equipment Household Oxygen Concentrator Generator Portable 1L Doble Flow Certification : ISO9001, UL, RoHS, CE. Noise Level : Ultra Low. Voltage : 220V. Purity : >94.5%. 5L Medical Oxygen Concentrator with Nebulizer Mr. Jason zhai Hefei Yameina Import and Export Co., Ltd Address:1st - 3rd Floors,No.2 Building,No. 9 Tian Hu Road , Hi-tech Development Zone Hefei City. Anhui Province,China.