This breakout board is much better than using a breadboard – because all of the pins are available in “triplets” with the GND and VCC, making it convenient to connect sensors and outputs with DuPont wires or server cables (watch the polarity and pinouts). When you put an for Arduino Nano in the black socket and this board allows you to easily connect to the various I/O pins and power. It has a 2.1 mm x 5.5 mm socket to apply power (just like an for Arduino Uno) and a 3.3 v regulator to supplement the 5v regulator on the Nano. The unpopulated pads along the outer edge are the correct spacing for 0.1 inch female headers and will allow you to use any for Arduino UNO compatible shield with a Nano. TLDR, it makes prototyping with an for Arduino Nano easier.
14 I/O Pin (servo type with GND, power and signal)
8 analog Pin with power output and GND
6 PWM Pin 1 Servo power input
I2C expansion Pin