Sea to Summit Spark Pro -9
Summary
Price At Time Of Writing | $999.99
Our Overall Rating | 92 out of 100
Pros - Lightweight, warm, features-heavy
Cons - Expensive and the lightweight fabric requires careful handling
Overall - A top-tier sleeping bag that delivers on performance, comfort and durability
Technical Specifications
Packed Size - N/A
Weight - 791g
Fill - 950-fill Ultra-Dry Down
Our Analysis & Ratings
The Sea to Summit Spark Pro -9°C Sleeping Bag is a high-performing, ultralight option made for people who want to stay warm without carrying extra bulk. It’s an upgrade from the earlier version, bringing in new additions while keeping the small pack size and lightweight feel that Sea to Summit is known for. With extra-lofty 950+ fill down, flexible venting choices and a smart baffle layout, it works well in three-season conditions and even handles mild winter nights.
Comfort - The 950+ fill down fluffs up nicely, keeping you warm without adding bulk. Its mummy-style cut wraps around your body and the shaped footbox gives your feet room to move. The soft neck and head collars help stop cold air from sneaking in and you can open the footbox or turn the whole bag into a quilt if you get too hot. If you sleep on your side, the mixed baffle setup helps keep the warmth even, so you don’t get cold patches through the night.
Construction - Sea to Summit used top-end materials to put the Spark Pro together. The outer shell is a light 10D nylon that holds up well but should be treated gently. The down has been treated with a moisture-repelling finish that helps it stay warm even when damp, though it’s not made to be fully waterproof. The baffles are designed to keep the down in place and prevent it from shifting, so you get steady insulation throughout. The Free-Flow Zip System is a highlight, giving you different ways to vent heat, including turning the bag into a quilt. The zippers also slide smoothly and don’t catch easily, which is rare in sleeping bags.
Features - The three-zip design (across the top, side and foot) gives you lots of options, including partially unzipping it so you can move around camp while wearing it. The fabric in the hood and foot area is water-resistant and breathable, helping protect against damp air or condensation in your tent. It also includes a stuff sack for packing down small and a roomier storage bag to keep the down fluffy when not in use. Some people might find the extra zippers a bit much, but they make the bag a lot more adaptable if you like having control over your setup.
Size/Weight - At just under 800g, the Spark Pro is very light for a sleeping bag that’s rated to -9°C. The regular size fits people up to around 6 feet tall (183cm), while the long version works for those closer to 6.5 feet (196cm). Despite having decent width (61cm at the shoulders, 53cm at the hips), it packs down to just 7 litres, which is easy to slide into your backpack. There’s enough space inside that you don’t feel squeezed in, but it still folds down nice and small when not in use.
Versatility - This bag is also great because of how many ways you can use it. Being able to unzip the whole thing into a quilt makes it perfect for warmer nights, and the -9°C rating means it’ll keep you warm when it gets cold too. You can even connect it with the women’s version for a double setup, though that’ll mostly appeal to a few. The multiple zippers mean it handles changing temperatures really well, although if you’re camping in very hot weather, you might still want a thinner bag instead.
Overall - The Sea to Summit Spark Pro -9°C Sleeping Bag is a top-shelf pick for anyone who wants a great mix of warmth, low weight and flexibility. It does cost more than some others, but the high-end down, clever features and well-thought-out design make the price feel fair. It’s not just a sleeping bag, it’s more like a full system built for all sorts of conditions.
