This 2×20 pin header is breadboard pitch (0.100″/2.54mm) and is great for making a connection between boards that need to be removable. This specific version has two rows of male 20 pins and can be used in place of a normal header when soldering to the Raspberry Pi Zero. Unlike standard Pi GPIO headers, this features a 90 degree right angle in the pins for the odd situation where a board needs to be mounted perpendicular to whatever it may be connected to!