The problem with baffles on sleeping bags? The down can shift around inside, creating cold spots. But on the TUMBLE MOUNTAIN 20, BIG AGNES‘s designers are using a new technique: injecting down into the fabric sleeves along with small, internal mesh barriers that keep it in place. The process requires longer baffles, so Big Agnes ran them lengthwise, making it unlike any performance bag we’ve seen. Available spring 2010, $290; bigagnes.com

竖条的baffle，防止乱跑绒，不过听说有很多纱网做内部小格，估计重量轻不了。