This is a filter, with the labels being the filter.

FORBES: On The New Record and Finding Success by Giving Away Music

"One of the things that is unique about this filter is even if you didn't have arsenic in the water and you only had iron, this is still a great filter to filter iron, " said David Nunley.

BBC: Water filter set to save lives

This used to make me crazy because the point of a spam filter is to make spam go away.

FORBES: The Best Technology Is the One You Seldom See

This is not the same as having a weblog or e-zine sitting on a public server which does not filter incoming requests.

BBC: Opening up the libel boundaries