Sea to Summit Spark Pro -1C Down Sleeping Bag

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UOG TOP PICK—The Spark Pro is an upgraded Spark sleeping bag from Sea to Summit, featuring higher-quality down and improved ventilation options. The bag has a fully detached left-side zip, a foot box zip, and a shoulder-length zip on the right side. The outer fabric has been upgraded to a uniform 10-denier Nylon, with a waterproof hood and foot box material for protection.

Sea to Summit says: 

The Spark Pro sleeping bag is the perfect option for lightweight adventures that puts comfort at the forefront. With the ability to be adapted to a range of conditions, the Spark Pro is as lightweight as it is versatile and functional. The optimal warmth to weight ratio makes this bag as comfortable as it is compact and easily packable

Our Verdict

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 treated with Sea to Summit’s Dry Down coating, which enhances the down’s ability to loft effectively in moist conditions, repel water, and dry rapidly.

The baffle design remains the same as the Spark, featuring vertical baffles across the chest to prevent down migration and horizontal baffles throughout the lower body. 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 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 for a more ‘traditional fit’. For fans of the classic Spark, there are many changes to celebrate.

– Reviewed by Ultralight Outdoor Gear

Features

• Goose Down with Ultra Dry Down treatment for improved water resistance in damp conditions.
• Featuring 10 Denier Nylon and 10D Nylon, these lightweight fabrics offer breathability, protection and effective temperature regulation.
• 10D Nylon’s waterproof and breathable features offer added protection and prevents exposure to tent wall condensation.
• The Free Flow Zip System offers temperature regulation and multiple sleeping bag configurations for added freedom in the outdoors. The minimalist 1/4 length secondary and footbox zips are ultra lightweight for added versatility and comfort.

Specifications

Temperature Rating

• EN13537:2012 Comfort: 3°C | 37°F
• EN13537:2012 Comfort Limit: -2°C | 28°F

Regular Specs

• Weight: 637g (excludes storage bags)
  
• Fill weight: 310g
  
• Fits up to: 6 ft / 185cm
• Internal Width Shoulder: 155cm
• Internal Width Waist: 135cm
• Internal Width Feet: 102cm
• Compressd Size: 8L

Long Specs

• Weight: 692g (excludes storage bags)
  
• Fill weight: 356g
  
• Fits up to: 6 ft 6 in / 198 cm
• Internal Width Shoulder: 165cm
• Internal Width Waist: 145cm
• Internal Width Feet: 112cm
• Compressd Size: 8L

Fit

• Mummy Fit: Fitted cut with generous footbox and technical hood, to maximise thermal efficiency and minimise bulk and weight.

Materials & Construction

• Insulation:950+ FILL Power, RDS- certified, Goose Down with Ultra Dry Down treatment for improved water resistance in damp conditions.
• Fabric: 10-Denier Nylon shell and lining.10-Denier Nylon waterproof-breathable hood and footbox.
• Zipper: Free Flow Zip System: Primary zip – full length #5 with zip-plow and two sliders.
  Secondary zip – 1/4 length #3 with zip-plow and two sliders.
  Footbox zip – #3 with two sliders.
• Baffle Construction: Vertical chest baffles, horizontal baffles lower half and base, box wall baffles top half of bag and sewn throughquilted construction lower half.
• Collar: Fitted front draft collar: scalloped over the neck and oversized at the shoulders.
• Hood: Technical fitted hood with soft touch adjustment. Extra deep for cosy like feel.
• Draft Tube: Single, down-filled, draft tube along the top of all zippers.
• Intergration: Pairs with Women’s Sea to Summit bags, and STS quilts.

Help & advice:

• The Ultimate Guide to Lightweight Sleeping Bags
• Time-Saver Guide to Choosing a Sleeping Bag
• Sea to Summit Sleeping Bag & Quilt Guide
• About Sea to Summit
• The EN13537 Standard
• All About Down