The Therm-a-Rest Vesper 20 represents the pinnacle of ultralight backpacking sleep systems, targeting three-season backpackers who demand top-tier insulation without the bulk and weight penalties of traditional mummy sleeping bags. Sporting premium features such as 900-fill-power down, a draft collar, pad attachment straps, box baffling, and a 10-denier fabric shell, it’s exciting to see such a high level of quality in a stock, off-the-shelf quilt compared to the custom-made quilts many backpackers use.

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I tested the Regular version; there is also a Long version (which is also 2 ounces heavier).

• Quilt Weight (manufacturer’s): 19 oz / (actual 20 oz)
• Compression stuff sack weight (tested): 1.7 oz.
• Tested Comfort: 32 degrees (F) – ISO; Lower Limit: 20 degrees (F) – ISO
• Gender: Unisex
• Dimensions: 75 x 58 x 4.5 inches
• Fits a person up to 72” (6 feet) / 1.83 meters
• Footbox: Closed
• Compressed volume: 3.1L
• Down Fill: 12.5 oz. (0.354 kg) of 900 Fill Power, PFAS-free, Goose Nikwax Hydrophobic Down, RDS (Responsible Down Standard) certified
• Shell and lining material: 10D (denier) nylon ripstop
• Pros: High Fill Power Down, Ultracompact, Draft Collar
• Cons: None, honestly.

Premium Materials and Design

The Vesper 20 is insulated with 900-fill-power, PFAS-free Nikwax Hydrophobic Down, among the highest-quality insulation available in outdoor gear. This premium down maintains loft even in humid conditions, a crucial advantage for backpackers facing unpredictable weather. The hydrophobic treatment allows the down to dry faster and retain insulation properties when exposed to moisture, addressing one of down’s traditional weaknesses.

The Vesper 20 uses box baffles, which are three-dimensional chambers, to hold the down in place, maximizing warmth and preventing the down from shifting. This keeps the insulation evenly distributed, ensures consistent loft, and eliminates cold spots. It’s a premium construction method found on higher-grade quilts.

The draft collar snaps behind the neck, and a drawcord tightens it around your neck so heat doesn’t escape.

The shell and liner fabric utilizes ultra-lightweight 10-denier ripstop nylon, which is soft and silky to the touch, striking a good balance between weight savings and durability.

Draft-collar and neck cinch

The Vesper 20 has a draft collar, a down-filled tube that you tighten around your neck to prevent warm air from escaping at the top of the quilt. When you’re ready for bed, you’ll snap the draft collar closed and stick your head through the opening from inside the quilt rather than trying to snap it closed around your neck. Once your head is through and you’re lying on your back, you can reach through the head opening and pull a thin, easily reachable drawcord, offset to the left, to cinch the draft collar around your neck.

The quilt’s extra width wraps around the edges of your pad, helping to eliminate side drafts.

Extra width and side draft protection

The Vesper quilt is 58” wide, which is wider than many companies’ wide quilts! While it tapers down to the footbox, it remains wide across the shoulders and hips, dropping over the edge of your sleeping pad to prevent side drafts from chilling you. The quilt’s pad attachment anchors (the straps can be removed) are not attached to the edges of the quilt but are instead placed inside it, creating, in effect, side draft tubes while ensuring proper quilt positioning. This is especially great for first-time quilt users because it eliminates the nuances of strap and connector positioning found on many custom-made quilts. The Neve Gear Waratah Quilt, made in Australia, anchors its straps similarly to prevent side drafts. 

SynergyLink Pad Connector Straps

The Vesper 45 comes with two pad connector straps called SynergyLink, which are simple elastic straps that wrap around a sleeping pad but offer no adjustability. Thin plastic toggles hook into tiny loops on either side of the quilt, closer to the chest or the waist, in one of two positions. However, they’re optimized for use with a 3″ thick inflatable pad, which might lead to some loft loss if you use a 3.5″ or 4″ thick inflatable pad (these are more prevalent) because the quilt is pulled more tightly around your body.

The Vesper 20 footbox is sewn closed.

Closed Footbox

The Vesper is a sewn-end quilt with a box-shaped footbox that allows the toes of back sleepers to point upwards without being cramped. If you’re too warm, you can simply kick your legs out to the side to cool off. There’s not really enough room to stick your sleeping pad inside the footbox, so you lay your feet on top of it (this is pretty standard with top quilts). The pad straps around your legs and torso will keep you correctly positioned on the pad.

Recommendation

The Therm-a-Rest Vesper 45 Quilt is a high-quality, ultralight, and ultracompact quilt that I found to be true to its temperature rating. It’s a great option for backpackers and fastpackers looking to minimize weight and bulk from their kit without minimizing features. There are ultralight quilts on the market that save weight with minimal features, but the Vesper manages to keep its weight low while maintaining features found on much heavier quilts through high-quality materials and smart design. If you want to reduce your backpacking sleep insulation weight this year with a highly compressible quilt, the Therm-a-Rest Vesper 20 deserves serious consideration. 

Disclosure: Therm-a-rest donated a quilt for an honest review.

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