1. Current overload or line surge shutdown 2. High temperature compressor shutdown. 3. High pressure alarm shutdown. 4. Low pressure alarm shutdown. 5. Low oxygen cocentrator alarm. Oxygen concentrator: 0.5-5L/min Purity: 95%+_3% Working system Continuous Power Supply AC230V.50Hz/AC220V.60HZ AC120V.60Hz Power: 390VA Net Weight: 16kg( Gross weight: 18.5kgs) Warranty: Long-life compressor designed for 1000 hours of maintenance-free use. Size: 33*26*54cm