All One Planet sleeping bags use YKK zips, because the last thing you need is a busted zip… The zips are bi-directional, with twin zip sliders allowing you to vent the bag from the foot on balmy nights. (The exceptions are the Winter Lite, Nitrous and Cocoon, where the zips do not go across the feet.
Providing you have a left- and right-hand zip opening, most of the range will zip together. (However, joining two bags together will actually decrease their thermal efficiency.) The zip pulls glow in the dark to save fumbling in the dark, while fabric near the zip is firmly sewn off to prevent the slider snagging.
One Planet mummy and tapered rectangular bags have ground-level zips and seams, with the vertical baffles wrapping right over your body to the ground. In contrast, the side seams of conventional bags are at the midpoint of the bag, allowing the insulation in the bottom of the bag to fall down away from the seam, creating cold spots.
All One Planet sleeping bags have a differential cut, with the inner fabric cut narrower than the outer shell. This reduces fabric waste, promotes proper lofting of the down, and protects the fill from compression.
Hood and foot
‘If your feet are cold, put on a hat.’ So the saying goes, and if you substitute hood for hat, you’ll understand why we go to so much effort. The hoods on all mummy and tapered rectangular bags are shaped to contour to the head, leaving only the nose and mouth exposed. They integrate with the neck muff and shoulders and can be cinched tight without compressing the fill. Three-dimensional foot cavities are used on all One Planet mummy and tapered rectangular bags, preventing your toes from compressing the down and causing cold spots (and cold toes!)
Draft tube and neck muff
One Planet sleeping bags use dual, D-shaped, three-dimensional draft tubes to stop any cold breezes at the zip. (The Robin Hoodless and Nitrous have single draft tubes.) Fabric near the zip is firmly sewn-off to prevent the slider snagging.
All One Planet bags (except the Cocoon, Nitrous and Robin Hoodless) have three-dimensional neck muffs: an elasticised collar that works independently to the hood, stopping warm air escaping from the neck and shoulders when you move during the night.