Features:
Size: 31mm x 22mm;
Main chip: NE555;
Input Voltage: 5V-15VDC. when power supply is 5V , the output current can be 15MA around; when 12V power supply, the output current can 35MA around;
Input current: >=100MA
Output amplitude: 4.2V V-PP to 11.4V V-PP. (Different input voltage, the output amplitude will be different)
Maximum output current: >=15MA (5V power supply, V-PP greater than 50%), >=35MA (12V power supply, V-PP greater than 50%) 
Output with LED indication(low level ,LED will on; high level,LED will off;low frequency, the LED flashes);
The output requency range is selectable: LF file: 1Hz ~ 50Hz IF file: 50Hz ~ 1kHz High-frequency file: 1KHz ~ 10kHz HF file: 10kHz ~ 200kHz
The output duty cycle can fine-tune; duty cycle and frequency is not separately adjustable; adjusting the duty cycle will change the frequency; 
The output frequency is adjustable:    Period T = 0.7 (RA +2 RB) C    RA, RB is 0-10K adjustable;    Low profile when C = 0.001UF;    IF stalls C = 0.1UF;    High-frequency file C = 1UF;    HF stalls C = 100UF; so buyers can calculate the frequency of the waveform. Application:As a square wave signal generator,generates a square wave signal used for experimental development.Used to drive a stepper motor for generating a square wave drive signal.Generate adjustable pulse for MCU.Generate adjustable pulse,to control circuitry associated.