Sea to Summit Altitude Sleeping Bag

This bag is cut with a wider hip-to-knee ratio to accommodate natural movement and prevent the fabric from stretching tight, which can create cold spots. It also features body-mapped insulation that places extra warmth in key areas where women tend to lose heat faster.

The Free-flow zipper system allows you to fully unzip the bag, effectively turning it into a flat quilt or comforter. It is a genuine feature that works well for warmer nights when you want to drape the bag over yourself rather than being zipped inside.

The 15-degree rating is a solid baseline for three-season use, but comfort is subjective. Because it uses a mix of 750+ loft down and Thermolite insulation, it retains heat well, but you should always pair it with a high-quality sleeping pad to prevent heat loss to the cold ground.

The maximum user height for this bag is 67 inches, or 5'7". If you are taller than that, you will likely find the bag too restrictive in length, which can compress the insulation at your feet and head, reducing its thermal efficiency.

It compresses down to 8.1 liters, which is quite compact for a 15-degree bag. It should fit easily into the bottom compartment of most 40-to-50-liter backpacking packs without taking up excessive room.

The 20D nylon shell is a standard balance between weight savings and durability. While it is water-resistant and tough enough for typical backpacking use, you should still be mindful of sharp rocks or sticks to avoid tears.