When you’re camping out in the wild you want a sleeping bag that you can rely on no matter what the conditions throw your way, and in Mountain Hardwear’s Hyperlamina Park 35, you get exactly that.

This bag has been designed for serious alpine adventures. It’s the highest performance synthetic fill bag on the market, lighter and warmer than all of its synthetic competitors. Essentially Mountain Hardwear’s design team have taken all of the benefits of a down sleeping bag, and recreated them in synthetic form.

The key to the Hyperlamina’s warmth lies not just in its fill (of which more later) but in the other details which help trap and maintain your body heat. Thermally-mapped insulation and a half-length centre zip are just some of the details that contribute to its heating efficiency, but the real genius is in the way in which the bag is put together.

“This is a bag that retains heat a whole lot better than your average synthetic bag”

The traditional construction of a synthetic sleeping bag would mean that there are cold spots where the stitching runs, but the laminate construction of the Hyperlamina sees the Thermal.Q insulation welded to the shell and lining in order to remove cold spots cause by traditional stitching. The insulation is placed tactically throughout the bag, with less planted in the areas where you are likely to overheat and more insulation concentrated on places where you need it most; in your core and feet. The mummy-style cut of the bag ensures the heat stays in, and the end result is that there are no cold spots in this sleeping bag at all.

The Thermal.Q insulation is worth a closer look – Mountain Hardwear maintain it, “has outstanding compressibility and maintains excellent loft.” Certainly this bag packs down nice and small (impressively small for a synthetic bag) and of course unlike down, synthetic insulation doesn’t suffer from a serious reduction in performance when it’s wet.