1. Onboard NE555 Chip 2. Single-Channel Signal Output, Output Duty Cycle Is About 50% Square Wave 3. Onboard Adjustable Resistor, Adjusting The Resistance Value Can Control The Output Frequency 4. Onboard Power Indicator Light 5. NE555 Pulse Generator Type: NE555 Pulse Generator Working Voltage: 5~12V Size: About 29x12mm Note: Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use Colour:As Shown Material:PCB Package Contents: 5 x Signal Generator Module Only the above package content, other products are not included. Note: Light reflection 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.