Dylan wrote an answer about Black Diamond Neutrino Rackpack - 6 Pack on July 16, 2012
I would add that these biners are smaller than average (one reason they are so light) which makes them slightly more difficult in some situations. Those situations might be: tripling up a double length sling, clipping bolts, clipping your rope or any situation where you have more than one piece of webbing/rope going through the biner. They are really light and the color coding is really useful (though unnecessary). I use them for my racking my cams but not for slings/runners.