Traverse Synthetic Sleeping Bag

WaveLoft™ is a unique construction technology designed to maximize loft and minimalize insulation weight. Instead of conventional flat layers of insulation (sewn flat on top of each other) or shingle layers (sewn in diagonally overlapping layers), WaveLoft™ creates curved layers which expand out from the shell to trap the greatest amount of air possible at a lower overall weight than existing synthetic insulation constructions. WaveLoft™ is used on all Sea to Summit synthetic-insulated sleeping bags, regardless of price level.

Thermolite® HL-1 is part of the family of Thermolite® materials used in Sea to Summit sleeping bags, sleeping bag liners and sleeping mats.

HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provides excellent lightweight warmth with superior durability. The Thermolite insulation lofts up inside the Air Sprung Cells™ of our sleeping mats to prevent convective heat loss from your warm body to the cold ground.

Down and synthetic bags identified with our zip coupling symbol use a 65 inch #5 YKK full-length zip which allows a unisex left-handed and women's specific right-handed bag to pair together.

Designed to pair side by side, each person sleeps in their own bag enabling each of you to take advantage of your bag's unique insulation zones, hood and footbox features - perfect for cozy adventures for two.

Bags with full-length #5 YKK zips on both sides can also be coupled together with other pairing bags.

Our Free-Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and multiple ventilation options when it's not. The half-zip on the right side of the bag (left side on women's bags) provides freedom of movement for both arms, additional ventilation and allows the top third of the bag to be folded down as a mini quilt when the mercury climbs higher than expected.

Sea to Summit sleeping bag fabrics and insulation are made without PFAS compounds. The non-PFAS DWR finish on the shell helps prevent the insulation from becoming damp if the bag comes into contact with moisture, such as tent wall condensation.Ultra-Dry Down is a non-PFAS hydrophobic treatment that absorbs less moisture and dries more quickly. It does not affect the 'breathability' or the lifespan of the down and lasts through at least 20 washings. The down used in our sleeping bags is responsibly sourced.Sea to Summit Dry Bags, Stuff Sacks and Compression Bags use a non-PFAS Durable Water Repellent finish to help shed water. Big River bags use a non-PFAS PU coating.