It is small but has many functions and is easy to operate and carry.      It can be used with an oscilloscope to test and debug electronic circuits, frequency response and impulse response of audio amplifiers.      Square waves are suitable for adjustment of oscilloscope attenuators and probe impulse responses.      It also calibrates the time factor of the oscilloscope.      There is a filter (which can be turned on and off) to suit the output of sine and pulse waves.            Output signal type: sine wave, square wave, triangle wave, positive and negative sawtooth wave.      Frequency range: 1Hz-500kHz for sine wave, 1Hz-20kHz for other waveforms.      Resolution: 1Hz      Sine wave distortion: 1kHz less than 1% or less, 1kHz less than 0.5% or more.      DC offset range: +/- 10V (can be turned off)      Output range: +/- 10V (PP)      Output Impedance: 50ohm      Power supply voltage: DC3.5-10V      Colour: as shown      Material: ABS            Package Contents:      1 * Signal generator      1 * USB cable            Only the above package content, other products are not included.      Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.