Working voltage: 4.5V-5.5VDC (DC socket power supply, positive inside and negative outside, do not connect in reverse). FM range: 87MHz-108MHz. FM step: 0.1MHz increments; press and hold the FM key to increase or decrease frequency continuously. Functions: Digital frequency display, power-off memory, and power-saving mode. Power-off memory: After power is restored, the radio resumes playback from the last tuned station. Power-saving function: Upon power-on or when the FM button is pressed, the digital display shows frequency for 5 seconds then automatically turns off to conserve power. This also reduces audio interference, resulting in clearer sound. Applications: DIY digital radio projects, microcontroller learning, electric vehicles, motorcycles, and other devices requiring radio integration. This product is a kit component and requires self-soldering. Color: As shown in image. Material: ABS+PC. Package Contents: 1 x Radio kit Note: Light reflection and differences in display screens may cause slight variations in color between the image and the actual item. Measurement error allowance: +/- 1-3 cm.