This is a very basic double sided prototyping board with standard 0.1" spacing with a 4x3mm (0.16x0.12") holes for mounting.The leaf pads makes you great for quickly prototyping stackable circuits.You can not only solder DIP components but also solder SMD components.

You can solder the digital & analog IO pins and plug it into Arduino,so that the proto board can directly communicate with Arduino like a simple shield. See the following picture,a simple light water project with Arduino.