Four sided monocoque construction
The Tundra bag is made in a four sided monocoque (coffin shape) construction. The box shape is warmer as it wraps around the body and allows for more natural positioning of the zip baffles. It also keeps the zipper away from the cold ground.
Hood piece and neck collar
This side section of the hood area shows the neck collar which is higher behind the neck than under the chin. The back of the back is much higher than the front and also when you sit up in a bag you need the back to be higher.
The trapezoid shaped foot piece
Trapezoid Shape with the zipper on the top edge away from the ground.
Standard shape with a top and bottom and the zipper next to the cold ground.
Flap over zipper, draw cords and cord locks
The design of the TUNDRA bags feature hidden elastic draw cords being easier to use with cleaner lines and less to catch. Combined with one handed cord locks this design keeps hood area uncluttered and neat and tidy.
A feature on the Simply Green Sleeping Bags. The double zip design is particularly useful for rescue teams to aid injured persons to be kept warm.