We're working out what we think - we'll add our view here!
Mountain Equipment says:
Unique baffle construction gives expedition warmth with the low weight and packsize required for weight critical objectives. Our dual layer offset baffle construction is combined with a heat reflective internal fabric to make the Trango a light, mobile and highly packable duvet. With levels of insulation that would only normally be possible with heavier and bulkier box wall jacket this is the perfect choice for remote trips.
Material & Construction