Feature: 1. Ultrasonic Starter Kit: Learning kit for R3, including ultrasonic sensors and stepper motor drive board, providing comprehensive teaching and a variety of experimental projects to choose from. 2. Flexible Use: This electronic component learning kit is flexible and scalable, supporting the use of other sensors and modules, flexible and diverse, suitable for beginners and professionals. 3. Stable and Reliable: This electronics learning kit has stable and reliable performance, strong scalability, and can be extended to other sensors and modules, helping you discover more creativity. 4. Complete Accessories: This kit includes relay, motherboard, digital tubes, ultrasonic sensor, stepper motor, buzzer, jumper cables, resistors, and other accessories, which are complete and practical. 5. Multi Specifications: This kit provides multiple specifications of LEDs, sensors, resistors, and modules, making it convenient for you to conduct different experimental projects and quickly improve your skills. Specification: Item Type: Electronic Learning Kit Material: ABS Plastic Battery Box Battery: 6 x 1.5V AA Battery (not included). Package List: 1 x Relay 1 x Main Board for R3 1 x Joystick 1 x 4 Digit Digital Tube 1 x 1 Digit Digital Tube 4 x Green Key Caps 4 x Buttons 1 x Servo 3 x Servo Plastic Bars 3 x Servo Screws 1 x 8x8 Dot Array 1 x Stepper Motor Driver Board 1 x Ultrasonic Sensor 1 x Active Buzzer 1 x Passive Buzzer 2 x Potentiometer 1 x L293D Chip 1 x For SN74HC595N 4 x Pin Headers 5 x Yellow LED 5 x Red LED 5 x Green LED 5 x White LED 3 x Photoresistor 1 x Flame Sensor 1 x Transistor 1 x Infrared Receiver 1 x Membrane Button 1 x Breadboard 1 x Stepper Motor 1 x 1602 LCD Display Screen 1 x Battery Box 1 x USB Cable 10 x Male to Female Jumper Wires 30 x Bread Wires 1 x RF Module Sensor 1 x RF Module White Board 1 x RF Module Inductor 10 x 10K Resistors 10 x 220Ω Resistors 10 x 1K Resistors 1 x Main Board Expansion Board 1 x Small Breadboard 1 x Joystick 1 x Water Level Detection Module 1 x Motor 1 x LM35 Temperature Sensor 1 x White LED 1 x Tilt Switch 1 x Plastic Box