This is a 2-pin polarized male header with 2.54mm pin spacing for vertical mounting on a PCB. It accepts the 2-pin housing into which you can insert wires that have had crimp pins attached to them.
Use this combination in your design for any 2-pin interface where you want to ensure that the user does not connect it the wrong way.
The picture to the right shows a 3-pin header.
Molex Part Number: 22-23-2021