Sierra Designs Night Cap 20° £160

+ Innovative zipperless design, clever features, comfy, affordable

- A tad heavy, style won’t suit everyone, risk of draughts, requires a good mat

This is the synthetic version of Sierra Designs’ Cloud 20° down bag. It’s £130 cheaper but 490g heavier and not as warm.

Like the Cloud 20°, the Night Cap 20° adopts an innovative design. There’s no zip, but the bag still opens wide thanks to a curved, wraparound ‘comforter’ – a duvetlike flap that pulls over your upper body. For some this will prove far comfier than a traditional bag. A big overlap between the comforter and the bag’s edge helps prevent draughts, while the zipperless design makes getting in and out easy.

Two other eye-catching design features include a vent you can stick your feet out of if you get too hot, and a sleeve for housing your sleeping mat. The latter provides excellent mat-to-bag integration and ensures the insulation is thickest where you need it most, which is above the body rather than underneath it (where it’d just get squashed anyway and perform ineffectively).

Eco credentials are top-notch – the insulation is made from 100% recycled water bottles and the 20-denier shell is also recycled – while the roomy cut doesn’t feel restrictive. Not everyone will be drawn to the unique design, but some will simply love it.

■ Fill 1134g of SierraLoft Eco Synthetic insulation (100% recycled) ■ Temp rating 1°C comfort, -5°C comfort limit ■ Weight 1370g

■ Pack size 38x19cm ■ Sizes Regular, long

Verdict

An innovative and well-priced synthetic bag with a zipperless design and clever ‘comforter’ – but the unique design might polarise opinion.