Typically used for 3½ floppy disk drives. 

Called a "Berg" connector.

AMP EI Series part numbers:

AMP / TE Connectivity 171822-4 – Cable socket

AMP / TE Connectivity 171825-4 – Vertical PCB header

AMP / TE Connectivity 171826-4 – Right Angle PCB header

Pin  Name     Color   Description
1    +5VDC    Red     +5 VDC
2    COM      Black   Ground
3    COM      Black   Ground
4    +12VDC   Yellow  +12 VDC