This is USB controlled relay opto-isolated board with 16 SPDT relays. You can use it for simple ON/OFF switching electrical devices - home lights, DC motors, solenoids and others. It can help you building projects like robotics and home automation.
This is a 240x128 liquid crystal matrix dot display that support English characters and even graphics, very suitable for interactive work with Arduino.
This brand new robotic arm is equipped with 3PCS NEMA 17 stepper motors. It moves and rotates much more smoothly than many other robotic arms in the market.