Fill power is the space that 1 ounce of down occupies, resulting in its insulation quality: a higher number means bigger clusters, so the same amount traps more air (read: warmth) with less weight.
Sierra Down Alternative Pillow
Once your head sinks into the cool, embracing surface of a Sierra down-alternative pillow, you’ll wish you could luxuriate in bed forever. We hand-stuff its silky, pure cotton walls with fluffy armfuls of 100% hypoallergenic Virtudown® filling, an exceptionally fluffy alternative-fill whose loft mirrors the texture and plush comfort of genuine goose down.
Then there’s Downright
Premium Virtudown® Fill