Extra header off Antec PSU?

[IndyJaws]

I've got an SX1040B with the 400 W Antec PSU. There is what appears to be a small 3 pin connector in addition to the standard molex and floppy power connectors. I can't find anything in the documentation saying what this is for. Can anyone enlighten me?

 

[bozo1]

It's to plug into a fan header on your motherboard so you can monitor the powersupply fan speed, if you wish. Totally optional.