Suitable use as a D.C. null detector in wheat stone bridges and potentiometers. It is main operated instrument and working voltage is 230 Volts. AC. 50 Hz. but can operate on a 6 volt battery also. The galvanometer has built in lamp and scale arrangement and housed in a bakelite case. The highly sensitive moving coil system is suspended in a taut band manner in a uniform field of permanent magnet. Galvanometer scale is 150mm long and is marked for both centre and end zero use. The spot of light can be set at any point on the scale with the help of zero adjusting knob. The sensitivity is controlled by a 2-pole, 6 way switch. The switch Positions are D, 1/10, 1/100, 1/1000 and s/c. time period 2 second, 1000 ohms