Sierra Designs Cloud 800 20¡ £290

+ Innovative quilt-like and zipperless design, impressive temperature ratings, venting options - Design won’t suit everyone

This sleeping bag is a maverick, adopting an innovative design that’s exceptionally comfortable. There’s no zip, but the bag still opens wide thanks to a curved, wraparound ‘comforter’ – a duvet-like flap that pulls over your upper body delivering a sensation more akin to your bed at home. A big overlap between the comforter and the bag’s edge prevents draughts, while the zipperless design makes getting in and out easy. With 419g of 800 fill power down and a -3°C comfort rating, warmth is impressive for the price. It’s versatile too: on warmer nights, fling open the comforter and stick your feet out of the footwell vent for a less clammy night’s sleep. Underneath the body there’s no down (it usually gets squashed anyway, compromising the insulation), and instead there’s a sleeping mat sleeve. This quilt-inspired feature ensures excellent matto-bag integration and keeps weight down. The 15-denier shell adds quite a bit of weight (due to all the design features), the cut may be too roomy for some, and the quilt-like design makes a good mat essential. But these flaws are minimal, when all-round comfort and warmth is so impressive.

■ Fill 419g of 800 fill power DriDown

■ Temp rating -3°C comfort, -10°C comfort limit

■ Weight 880g (regular)

■ Packed size 38x19cm

■ Sizes Regular, long, women’s

Verdict

A versatile, warm and extremely comfy bag with an innovative design – but the quilt-like approach won’t suit everyone.