This time around it's a synthetic belay jacket. Despite never getting really hot or really cold, lovers of the great outdoors know that the UK's weather ranks amongst the most unreliable and demanding in the world. There is no better example of this than at 0°c where water gets so cold it turns to ice, and ice gets so warm that it turns to water. A damp 0°c can feel as cold as -20°c when the wind is blowing, and a few frozen hours on a belay ledge may leave you regretting your choice to travel light. It is times like these that you could be forgiven for throwing it all in and moving to Spain, or to start walking around gear shops looking at the warmest jacket money can buy. My first time on Craig yr Isfa one wintery day saw me the next Saturday in Ellis Brighams drooling over a 80s Mountain Equipment Fitzroy, sod the weight.. it was waterproof and warm. Shame it was way more than my bar work budget could justify.

The development of the 0Hiro is important to us, we really want to get a garment like this right. I'm pretty sure the basics are already sorted but it's the little things we need to work on to make it a really great jacket. How big does the hood need to be without being too big? Are the cuffs wide enough or will that extra 5mm mean you can squeeze your gauntlets through easier. These are the nuances that make a good jacket into a great jacket and one that we won't need to tinker with for a while. We could of course do all this ourselves but invariably this means that the design gets tweaked around our own experiences, our own body shapes.

1. Toray Nylon Fabric

We have used the same fabric as we have been using for our PipeDream sleeping bags, it has been proven to be light, tough and has a decent DWR.

A belay jacket is designed to be oversized to fit over the top of all your other layers so it may appear baggy when you are not wearing those layers!

At the moment the hood fits over a Petzl Meteor so I am happy that it is big enough. However it would be good to get some feed back on a larger number of body shapes and helmet types. Does it stop spin drift blowing down your neck and hail beating your nose?

Only three at the moment; two big ones on the outside and one zippered on the inside. Can you get your gloves in the pockets? Are the accessible enough when wearing a harness or rucksack?

• Weight: Small 523g, Medium 555g, Large 568g, XLarge 629g
• 100% Nylon 15d x 25d ripstop using a “farrilo” hollow core yarn. It weighs just 29 g/m2
• 150g/m2 Non branded synthetic

Initial feedback is that you may want to size up from your normal, more everyday jacket. You don't even have to be a climber to appreciate this jacket, we've already had it being used as a change over jacket in the recent Mountain Mayhem 24 hour mtb race.