... GB/T 3785,IEC 651 Type 2,ANSIS 1.4 Type 2.It is widely used to test the ... protecting,working,sanitation, teaching search and other departments. Display: 10mm (0.4') LCD (Liquid Crystal Display) Function: LP , Leq ,LN. Frequency range: ... : electron Connector:RS232C Power supply: 4x1.5v AAA (UM-4 battery Size: 236 x 63 x26 mm Weight: 170g ( ... 2.RS-232 and software 3.External rela 4.Bluetooth interface