Black color common IDE type power connector, commonly referred to as a 4pin Molex connector. This is the type of connector usually found on IDE HDDs, CD/DVD drives, 5.25" devices, lights, some fans, etc. If you are going to use these with bare wires don't forget to buy the crimp pins that go with them. Note the drives use male pins and pin housings while power supplies have female pins and pin housings.