What Our Gearhead® Experts Are Saying: “I recommend this to ultralight backpackers who still want real comfort. It’s warm for the weight, the liner feels great, and the zipper vents let you tune temperature instead of sweating through the night.”Cold nights feel a lot less intimidating when your sleep system packs small and still delivers real warmth. The Spark Pro Down Sleeping Bag is built for fast-moving trips where you’re counting ounces all day but still want to wake up rested for another big push. Sea to Summit gives you a true three-season bag that doesn’t force you into a tight, restrictive fit when the temps dip.Inside, 950+ fill-power RDS-certified goose down with a non-PFAS Ultra-Dry Down treatment lofts quickly to trap heat efficiently, while highly breathable 10-denier fabrics keep the bag comfortable when conditions fluctuate. A technical hood, front draft collar, and anatomical footbox seal in warmth where it matters most. The Free-Flow Zip system adds real versatility—open the side, shoulder, or footbox zips to dump heat, or unzip the bag flat into a quilt when the night stays mild. For ultralight backpacking in the shoulder seasons, it’s a high-end blend of warmth, ventilation, and packability.
Responsible Collection: Responsibly Sourced, [stuff sack] bluesign® APPROVED, Recycled/Repurposed;
Material: 10D nylon, non-PFAS DWR treatment;
Insulation: 950+-fill goose down (RDS-certified), non-PFAS Ultra-Dry treatment;
Shape: mummy;
Zipper: Free-Flow;
Max User Height: [regular] 6ft 1in, [long] 6ft 6in;
Shoulder Circumference: [regular] 61in, [long] 65in;
Hip Circumference: [regular] 53in, [long] 57in;
Foot Circumference: [regular] 40in, [long] 44in;
Bag Length: [regular] 77.2in;
Draft Tube: draft collar, adjustable hood;
Pockets: none;
Pad Retainer: no;
Venting: 1/2-zip side;
Fill Weight: [regular] 16.9oz, [long] 19.4oz;
Degree: 15°F;
European Norm/ISO Comfort Rating: 27°F;
European Norm/ISO Lower Limit Rating: 15°F;
Storage Sack: not included;
Stuff Sack: 13L 40D recycled nylon compression sack included;
Stuff Size: [regular] 7L, [long] 7.9L;
Claimed Weight: [regular] 1lb 11.7oz, [long] 1lb 14.4oz;
Activity: ultralight backpacking;
Manufacturer Warranty: lifetime;
storecredits: 0.0;
Style Variants
Available Colors: Beluga Black
Size Reference for Sea to Summit Sleeping Bag: 15F Down
Available Sizes: Long, Reg
