Product News at UKC presents climbing, walking and mountaineering equipment posts that will be of interest to our readers. They are not gear reviews and are provided by companies that advertise with UKClimbing Limited.

It's the time of year for Summer Lightning: in May and June, ultralight down specialists PHD showcase their newest innovations in lightweight sleeping bags and clothing. For 2018, the focus is on two factors: taking the lightest gear to the absolute limits of what is possible, and increasing its flexibility. And if you increase flexibility, you need less kit…and your pack becomes lighter still.

Some of this may make it into the main PHD range, but really, it's safer to think of Summer Lightning as a short term chance to get hold of some pretty extraordinary kit.

Superlight Sleep Systems

This sees PHD's pioneering "Sleep Systems" approach – a flexible, layered setup – twinned with the philosophy behind their game-changing Superlight bags. This lets them create, for example, a system that works from summer through to the depths of winter, at under 800g.

TOT*: +5°C/41°F (Inner bag) 0°C/32°F (Overbag) -15°C/5°F (Inner/Overbag together)

Weight: Inner: 315g/11oz Overbag: 480g/17oz Total: 795g/28oz

Price: £835

*TOT = Typical Operating Temperature

An inner bag and Overbag: use either of them solo, or slip one inside the other for maximum warmth. A -15°C bag weighing just 795g would be pretty remarkable in its own right, but this two-part outfit covers a range from -15°C right up to +5°C! The potential for year-round use or trips covering increasing altitudes is obvious.

PHD's exclusive 1000 fillpower down and 7 denier fabric really hammer the weight down, and water-resistant 'Hypershell' sheds moisture from the outer of the Overbag. The Combi packs into two tiny stuffsacks: easier to stow than one big bundle, and easier to unpack on single-layer nights.

TOT*: 0°C/32°F

Weight: 480g/17oz

Price: £466

*TOT = Typical Operating Temperature

New developments in lightweight fabrics have allowed PHD to really the capitalise on the weight-saving versatility of the layered-sleeping concept. This Superlight Overbag gives a 20°C boost to their lightweight sleeping bags – or functions as a 0°C bag in its own right – but still only weighs 480g.

So, if you team that with their ingenious Triobag, for example, you have a system which takes you from tropical summer to Alpine winter, for under a kilo!

"Triobag", you say? What's that? Well, funny you should ask…

TOT*: -5°C/23°F, +5°C/41°F or +15°C/59°F

Weight: 490g/17oz

Price: £534

*TOT = Typical Operating Temperature

One bag, three different configurations, three different temperature ratings.

This innovative little number has a down-filled middle layer, sandwiched between the top and the bottom. This means you can sleep under the extra layer when it's cold, or on top of it when it's warmer. The third option? That's the really ingenious part: whip it inside out and sleep under just the middle layer on balmy summer nights.

The design is obviously very clever and seriously versatile, so much so that you might have overlooked the other really impressive bit: it's only 490g.

PHD Down Jackets

TOT*: -15°C/5°F

Weight: 300g/11oz

Price: £399

*TOT = Typical Operating Temperature

PHD's original Yukon Jacket, created for the Yukon Arctic Ultra, was (and still is) impressively lightweight. Their 1000 fillpower 'K Series' version even more so. This one though: this one would have been simply unimaginable a few years ago.

So just how light is it? OK, get a can of pop. Take a decent gulp out of it. This jacket weighs about the same as what you've got left, and remember: this is a box-wall constructed down jacket, with a hood, in coated water-resistant fabric, rated at -15°C!

Alpine Ultra 7X Jacket © PHD

TOT*: -10°C/14°F

Weight: 250g/9oz

Price: £359

*TOT = Typical Operating Temperature

The idea behind the Alpine Ultra Jacket has always been to provide warmth on pre-dawn Alpine starts, spending most of the rest of the day packed in a tiny bundle in your rucksack. In fact, even in standard trim it's been described as the perfect Alpine jacket.

How do you make that better? It needs to be just as warm, but for a jacket that spends a lot of time being carried, being smaller and lighter would be a real bonus. And that's precisely what this is: the Alpine Ultra Jacket, in the lightest fabric PHD can get their hands on.