What is that barrel shape next to the SATA headers

[wldaniell]

On the D915 MB from Intel and on other boards I have seen a black horizontal barrel shaped component about 1/2 inch long and 1/4 inch in diameter that has a silver top. It is usually located near the SATA headers. It looks like either a capacitor in a sleeve or a reset button of some type but it does not appear to depress.

What is it?

Thanks

 

[kajabla]

Probably a capacitor?