The Arduino Leonardo (without headers) is a powerful microcontroller board based on the ATmega32U4. It features 20 digital I/O pins, 7 of which can be used as PWM outputs, and 12 analog inputs. Unlike other Arduino boards, the Leonardo can emulate a USB device, such as a mouse or keyboard, making it ideal for human interface projects. This version does not come with pre-soldered headers, allowing for flexible customization. It operates on an input voltage of 7-12V and offers micro USB connectivity. Perfect for advanced projects, it combines ease of use with powerful capabilities for creative, interactive applications.