This is a blue colored 40 Pin 2.54 mm?0.1"? Single Row Pin Header Strip from DFRobot.
These 0.1" header strips are commonly used as low-cost Arduino connectors. The standard spacing allows use with solderless breadboards, perforated prototyping PCBs, female headers, and our premium and pre-crimped jumper wires. The single-row header strips can easily be snapped into smaller strips to fit your application.