Flex—it really does turn a regular night's rest into something special. Stretch baffles move with your tosses and turns during the night, making the Diamond Springs more comfortable, but also more thermally efficient, too. Sleep warmer, sleep better, period! Six-hundred-series goose down maintains its loft year after year and Sierra Designs' legendary details, like Pad Locks and an Ergonomic Hood, make the Diamond Springs your own private oasis.