Even in those warm summer months, as soon as you get up high or down low near water, that chilly quilt or bulky old bag you've been using since high school is not cutting it. The Big Agnes V Notch UL 40 is a highly compressible sleeping bag with a cozy lining of incredibly lightweight and packable Primaloft® Hi-Loft Ultra Silver insulation. It will keep you warm and keep your pack light, whether that's a backpack, bikepack or packraft.