Features: 1. This is a 24-hour digital circuit clock kit that uses CD4518, CD4511, CD4081, CD4013, CD4060, and other integrated circuits. The circuit does not include a microcontroller, so it operates without programming, and allows calibration of hours, minutes, and seconds. It does not have an alarm function. 2. The kit includes a second signal generator, counter, decoder display, and timing circuit. The second pulse is derived from a high-frequency signal generator to produce a precise 1Hz square wave signal for accurate timekeeping. 3. Suitable for educational training and soldering practice, ideal for DIY electronics enthusiasts. 4. Made from high-quality materials with reliable performance and long service life. 5. Features a red digital tube display for clear and easy-to-read digits. Color: Black Material: PCB circuit board + electronic components Note: This product is a DIY kit. It is not pre-soldered and requires basic soldering skills and assembly. Size: 12.92 cm x 7.86 cm Package Contents: 1 x Circuit board 1 set Electronic components (DIY parts) Only the items listed above are included; other accessories are not included. Note: Lighting effects and differences in display screens may cause slight variations between the color shown in the image and the actual product. Measurement tolerance: ±1–3 cm.