The new for spring 2015 HyperLamina Spark is, says MHW, the 'highest performance synthetic bag on the market' thanks to a combination of the company's proven Lamina welding technique where the fill is welded to the shell and lining to eliminate stitching and the resting cold spots and cunning zoned placement of different insulation weights to place warmth where it's needed.
- £180 / 886g (including stuff sac)
- Welded Lamina Construction
- Thermal.Q synthetic insulation
- Body-mapped insulation distribution
- Half-length centre zip
- Performance Mummy Cut
- Face gasket and tailored hood
- Compression stuff-sac and storage sacs included
- Packed dimensions: 24cm x 17cm (measured)
Comfort: 5˚C / Comfort Limit: 0˚C / Extreme: -16˚C
Ask for opinions on the 'best synthetic sleeping bag' and Mountain Hardwear's Lamina range is generally near the top of the list. The Lamina welded construction which bonds the fill directly to the liner and shell of the bag eliminates stitching, which in turn minimises seam-liine cold spots. It means the bag works harder and it's become the darling, in particular, of UK lightweight bivi fans, who know it's a question of 'when' rather than 'if' their sleeping bag will get damp.
New this spring, the HyperLamina range ups the ante again. It uses the same Lamina construction and Thermal.Q synthetic fill, but with additional tweaks to up efficiency and reduce weight and bulk. In particular, the HyperLamina bags use different insulation weights in different areas for added efficiency.
The core and foot area in particular get added warmth while the underside is noticeably thinner. Seems like sound reasoning - put the insulation where you really need it, save weight and bulk where you don't. Get a lighter bag and a smaller pack size.
The latter's certainly true: the Spark compresses down to a neat (measured) 24cm x 17cm in the highly water-resistant 63g, Sil-Nylon compression sac supplied. And while our actual 823g is heavier than MHW's 788g claim, it's still decently light for a synthetic bag that'll cope down to freezing point.
That puts it not far off a Rab Neutrino 400, though the down bag is around 3˚C warmer all round) or an ME Helium 400 with similar stats, but the HyperLamina is a fair bit cheaper than both down options and has the day-to-day reassurance of being synthetic.
In design terms, the bag's a classic mummy shape, with a roomy comfortable foot-box, but tweaked. It has a vogue-ish central half-zip that's double-ended so you can use it for venting, but there are also Velcro dots to hold things together and avoid billowing. Thoughtfully the rough bits of Velcro - hooks - can be anchored to handy supplementary dots to stop them catching on your fleece pyjamas. There's an insulated baffle too.
It's all easy to use, ideal for cooking while still mostly in the bag, and the adjustable hood - simple drawcords - fits well too.
The holy grail of a synthetic sleeping bag that's comparable in weight, warmth and pack size to down - but cheaper, more rugged and more water resistant - is still tantalisingly out of reach, but despite weighing slightly more than MHW claims, the HyperLamina Spark really isn't far off.
Which means for the sort of damp conditions, bivi-type camping where synthetic bags make sense, the Spark looks like being an ideal choice.
For full details see www.mountainhardwear.eu.