Read up on Sam from the Exeter store’s thoughts on this Aussie brand’s lightweight performance sleeping bags.

Over the last few weeks, I’ve been lucky enough to try out the Sea to Summit Spark III. Packing 400grams of 850+ Fill Power down and a comfort rating of -4 the Spark 3 is an awesome bit of kit especially when you realise that all this weighs just 642g in total.

To try this incredible bag out I decided to take it out to Dartmoor for a night under the stars. Starting in Okehampton we would follow the high ground to Black tor before descending the valley to camp near a freshwater source. Due to this taking place after work we would have to find our way in the dark giving us all the opportunity to touch up on our night nav!

I have always been a fan of packing light and this is something I wanted to take to the next level with this short trip. The Spark 3 sleeping bag certainly helped with that, Due to its incredible pack size of just 15x35cm, I was able to fit all my kit into a 35L backpack. Something I had been unable to achieve with my own synthetic sleeping bag in the past.

Once out on the moor, it was great to know I would be getting a good night’s sleep, The Spark 3 is designed to be lightweight but still provide the same warmth as similar bags. To do this Sea to Summit use 850+ Fill Power which indicates that 1 oz of down will re-expand to over 850 cubic inches after compression. The higher the loft, the less down is required to achieve the same temperature. Kept the bag light while also allowing me to get a good night’s sleep at 0 degrees. This coupled with the Spark 3’s light weight light-gauge #3 YKK zip and high-performance 10D Nylon shell and 7D lining results in an ultra-light sleeping bag that isn’t compromising on performance.

The Spark 3 is also boasting Expedition Mummy bag sizing, this gives the user a little more wiggle room inside the bag. Ideal for adding or removing layers or just having a little more freedom of movement. I found this to be a great feature; I am sure you all know the feeling of having to leave your nice warm sleeping bag after a cold night on the hill. Well with this added room I was able to add a few layers before getting out, making the whole experience a little less painful!

Once up it was time to pack away, The Spark 3 comes with a generous stuff sack that helped me get the sleeping bag back down to the optimal size for repacking my equipment, It was also nice and easy to stuff the bag into which resulted in less time packing away and a little more time to enjoy a nice coffee before we headed back out onto the hill.

All in all, I was exceptionally impressed with this bag, the incredible pack size and overall weight meant that I was able to pack light without compromising on performance. I especially liked the idea of added wiggle room that made removing and adding layers easy. It would be great to see a 2-way zip in the future to allow for venting when the bag becomes a bit too warm but this is something I would happily sacrifice for the comfort this bag provided. I like this bag so much it has gone on my own list of wants!


Take a look at the Sea-To-Summit Spark Series HERE

This post was written by Sam, who can be found working hard at the Exeter Store. Sam completed a degree in Outdoor education and instructing at Marjon University before helping his old lecturer set up an outdoor education business teaching Bushcraft, Mountaineering, and Sea kayaking. In his spare time, Sam is a keen photographer and videographer often filming adventurous sports like climbing, kayaking, and mountaineering.

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