Sea to Summit Spark & Spark Pro Series Explained
Mar 03, 2025
The Updated Spark Series
Sea to Summit have redesigned its renowned Spark sleeping bag line. The Spark series continues to be made with high-quality materials, using 850+ ethically sourced down treated with Sea to Summit's Dry Down coating. This coating enhances the down's ability to loft effectively in moist conditions, repel water, and dry rapidly.
The baffle configuration remains the same, featuring vertical baffles spanning the chest to prevent down migration and horizontal baffles employed across the lower section. A draft collar has been added to help the bag retain warm air and prevent cold air from entering.
The outer fabric has been upgraded to a uniform 10-denier Nylon, eliminating the ‘see-through’ appearance of previous Spark bags. A significant improvement is the waterproof 10-denier Nylon material used at the hood and foot box. These areas are most likely to come in contact with the tent wall, which can suffer from condensation, especially in single-skin tents. This extra layer of protection keeps the down dry.
The hood has also been redesigned to provide a more ‘traditional fit’. For fans of the classic Spark, there are many changes to celebrate.
The Spark Pro Series
The Spark Pro builds on the recently updated Spark series of sleeping bags from Sea to Summit, with a few additions that make it a more user-friendly sleeping bag for the trail. The Pro opts for a 950+ fill power down (as opposed to the 850+ used in the standard Spark) of ethically sourced down for its insulation. The down has been coated with Sea to Summit's Dry Down, which improves the down's capacity to dry quickly, repel water, and loft efficiently in damp environments.
The baffle design is identical to that of the Spark, with horizontal baffles along the length of the lower body and vertical baffles across the chest to stop down migration. Notably, the upper baffles of the Spark Pro employ a box wall construction, eliminating cold spots and further reducing down migration, resulting in improved overall bag performance.
Besides the quality of the down used, one key difference between the Spark and the Spark Pro is their ventilation capabilities. The Spark Pro features a main left-side zip that extends three-quarters of the way down and can be detached entirely. Paired with the zipper in the foot box, the bag can open fully, just like a quilt. The foot box can also be opened separately, allowing you to stick your feet out when they get too warm. Furthermore, the bag has a shoulder-length zip on its right side, enabling additional ventilation options. Thanks to its versatile ventilation options, the Spark Pro boasts a wide temperature range and enables adaptable use across different seasons. It excels during transitional periods like spring and fall and mild winter days, providing great adaptability to changing temperatures.
The Spark Pro’s outer fabric has also been upgraded to a uniform 10-denier Nylon. The waterproof 10-denier nylon used for the foot box and hood is a major improvement. Particularly in single-skin tents, these regions are most likely to come into touch with the tent wall, which is susceptible to condensation. The down is kept dry by this additional layer of defence.
The hood, like the upgraded Spark, is also more ‘traditional fit’. The Spark Pro takes everything from the classic Spark and adds some exciting new upgrades.
Technical Features
The second highest-lofting down used in the Spark sleeping bags or quilts. 850+ Fill Power indicates that one ounce (30g) of down will re-expand to over 850 cubic inches after compression.
The QuiltLock system uses the snap locks located at the shoulder and foot end of Sea to Summit sleeping bags plus the quilt footbox/quilt straps to secure a quilt to the sleeping bag.
100% of the down used in our sleeping bags and quilts is independently certified to the Responsible Down Standard (RDS). The RDS certifies down against animal welfare requirements and tracks it from the source to the final product.
The highest-lofting down used in the Spark Pro sleeping bag. 950+ Fill Power indicates that one ounce (30g) of down will re-expand to over 950 cubic inches after compression.
Our Free Flow zip design* ensures your sleeping bag retains maximum warmth when needed and offers multiple ventilation options in warmer temperatures. The half-zip on the right side of the bag (left side on women’s bags) provides freedom of movement for both arms, offers additional ventilation and allows the top third of the bag to be folded down.
*Featured only on Spark Pro.
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.
Sea to Summit have redesigned its renowned Spark sleeping bag line. The Spark series continues to be made with high-quality materials, using 850+ ethically sourced down treated with Sea to Summit's Dry Down coating. This coating enhances the down's ability to loft effectively in moist conditions, repel water, and dry rapidly. The baffle configuration remains the same, featuring vertical baffles spanning the chest to prevent down migration and horizontal baffles employed across the lower section. A draft collar has been added to help the bag retain warm air and prevent cold air from entering.