Feathered Friends Petrel UL 10 Sleeping Bag Review

The Feathered Friends Petrel UL 10 Sleeping Bag is a women-specific 10°F ultralight sleeping bag designed for adventurers who want premium materials, lightweight performance, and reliable warmth in the backcountry. In this review, I share my experience with the Petrel UL 10 sleeping bag, including its fit, comfort, features, warmth, weight, and whether it’s worth the investment for campers and backpackers looking for a high-quality ultralight sleeping bag.

Feathered Friends Petrel UL 10 Sleeping Bag Specs

The Petrel UL 10 sleeping bag is designed specifically for women, with a slightly narrower shoulder area and more room in the hips and feet. It also includes extra down in areas where women often feel colder, including the footbox and chest.

Key Specifications

Feature	Details
Temperature Rating	10°F / -12.2°C
Fill Power	950+ Fill Power Goose Down
Packed Size	11L
Zipper	Right-side #5 YKK two-way zipper
Shell	Pertex® Quantum Pro® 7D × 30D ripstop
Lining	Flyte 10D recycled nylon + Pertex® Diamond Fuse 15D footbox
Shape	Women’s mummy
Origin	Seattle, USA (using imported materials)
DWR Finish	Made without intentionally added PFCs/PFAS

Petrel UL 10 Sizes, Weight, and Dimensions

Petrel UL 10 Sizing	Small	Medium
Ideal Sleeper Height	5’3″ (160 cm)	5’9″ (175 cm)
Dimensions	57″ shoulder / 62″ elbow / 59″ hip / 41″ footbox	57″ shoulder / 62″ elbow / 59″ hip / 41″ footbox
Fill Weight	1 lb 4 oz (565 g)	1 lb 5 oz (595 g)
Average Weight	1 lb 13.8 oz (846 g)	1 lb 15.6 oz (895 g)

My review is for the women’s Petrel UL 10. Feathered Friends also makes a men’s equivalent: Lark UL 10. While I chose the Petrel because the women’s-specific cut works well for my body, the Lark has a slightly different shape with more room through the shoulders and elbows, making it a better fit for some backpackers.

Measurement	Petrel UL 10	Lark UL 10
Shoulder circumference	57″	59″
Elbow circumference	62″	64″
Hip circumference	59″	55″
Footbox circumference	41″	42″

Why I Chose the Feathered Friends Petrel UL 10 Sleeping Bag

When I started looking for a new sleeping bag, I knew I wanted something ultralight, but without sacrificing warmth.

My main priorities were:

• A snug fit for my slim frame
• Premium down insulation
• A great warmth-to-weight ratio
• Keeps me super warm

Petrel UL 10 vs Egret UL 20 vs Hyperlite Mountain Gear 20-Degree Mummy Bag

I narrowed my options down to three models that stood out for their warmth, low weight, and high-quality construction:

• Feathered Friends Petrel UL 10
• Feathered Friends Egret UL 20
• Hyperlite Mountain Gear 20-Degree Mummy Bag

While the Egret works well for 3 seasons, it might not be ideal for my winter tent camping. I also passed on the Hyperlite because I was concerned its slightly wider shoulder width would feel colder for my frame. Nighttime temperatures can drop below freezing on my Southwest winter trips, so the extra warmth is well worth the small weight penalty to me.

So ultimately, I chose the Petrel UL 10. If I’m cold, I don’t sleep, so those extra 4 ounces are a non-issue.

Here’s how the bags that made my shortlist compare on paper:

Feature	FF Petrel 10 UL	FF Egret UL 20	Hyperlite 20° Mummy
Temperature Rating	10°F	20°F	20°F
Fit	Women’s-specific	Women’s-specific	Unisex
Fill Power	950+ goose down	950+ goose down	1000 fill power grey goose down
Medium/Regular Weight	1 lb 15.6 oz (895 g)	1 lb 11.2 oz (770 g)	26.5 oz (752 g)
Packed Size	11 L	9 L	10 L
Shoulder	57″	57″	58.75″
Hip	59″	59″	57″
Footbox	41″	41″	40″
Why I Considered It	Warm 10°F rating, women-specific fit, and excellent warmth-to-weight ratio	Same premium Feathered Friends construction with lower weight for a lighter three-season option	Ultralight design, 1000-fill-power down, and a brand I also already love

Feathered Friends Petrel UL 10 Sleeping Bag Review

First Impressions of the Petrel UL 10 Sleeping Bag

Of course, the first thing I noticed when I pulled the Feathered Friends Petrel UL 10 out of the box was the color. I love that magenta, and the cerulean also looks exactly like in the photos on their website. Their colors are 100% accurate.

After unpacking it and letting it loft, it quickly expanded on my bed. When I first tried it at home, it felt like a furnace, which gave me a good sense of how much warmth this sleeping bag can provide, so I immediately knew I made the right choice.

There’s a noticeably firmer strip of fabric along the zipper track. It felt crisp and a bit noisy when handling the bag, which made me concerned about sleep noise at first, but it’s actually completely quiet when I’m inside.

The fabric feels soft, the construction looks solid, and essentially, every detail leads me to trust that my Petrel UL 10 will last me for years of adventures.

Feathered Friends Petrel UL 10 Fit and Comfort

I am 5’10” and 130 lbs, and I chose the Medium size. The fit feels perfect for me.

I have enough room to move around, bend my knees, and sleep on my back or on my side without feeling restricted.

The way the Petrel sleeping bag is designed, or cut, is slightly more fitted around the shoulders and neck. That reduces extra space around my upper body, so I don’t get any cold drafts at all, and it makes the bag more efficient at retaining warmth.

Feathered Friends Petrel UL 10 Sleeping Bag Warmth Performance

My first sleeps in my new Petrel UL 10 were during my July Sierra trips, when I car camped and backpacked in:

• Mammoth Lakes: approximately 8,600 feet
• Big Pine Lakes: approximately 10,000 feet
• Yosemite Valley: approximately 4,000 feet

Nighttime temperatures were warmer than what this sleeping bag is designed for, mostly in the upper 40s to low 50s Fahrenheit.

Even though I wasn’t using it in cold conditions, it performed exactly how I hoped. Obviously, I never felt cold, but I also had plenty of ways to regulate temperature with the zippers and fasteners around the neck.

In Big Pine Lakes, I had condensation issues for a few nights because it rained and was super humid the rest of the time, and my rainfly may need a little TLC. However, the water droplets didn’t get absorbed into my sleeping bag much, though, and it dried very quickly. I think the Pertex Quantum Pro shell and its DWR finish played a big part in keeping that moisture from soaking into the bag.

My Sleep Setup

For backpacking, I paired it with a combined R value of 6.2:

• Nemo Tensor Insulated sleeping pad (R-value 4.2)
• Therm-a-Rest Z Lite sleeping pad (R-value 2.0)

For car camping, I used it with my Exped MegaMat Max sleeping pad, which has a much higher R-value of 10.6! Review coming soon!!!

I slept in:

• Merino 250 base layers
• Fleece-lined hat
• Heat Holders socks

I have not slept in the Petrel UL 10 sleeping bag in freezing temperatures yet, so I cannot say from personal experience yet at which temperature this bag will keep me alive versus warm. Based on my experience so far, though, the warmth and construction give me confidence that it will perform well when I eventually use it in colder conditions.

I’ll continue updating this review as I use my Petrel UL 10 sleeping bag in colder conditions throughout the year.

Petrel UL 10 Temperature Control and Comfort Features

On warmer nights, you can control how warm you feel in the Petrel UL 10 with its two-way zipper system. I leave the zippers fully open, using the bag more like a blanket wrapped around me, and secure it around my neck using the built-in fastener.

The hood and draft collar are also excellent. The hood cinches down when temperatures drop, and the full draft collar helps trap warmth around your neck and shoulders.

The hood is also the perfect size to fit my backpacking pillow!

Feathered Friends Petrel UL 10 Weight and Packability

At just under 2 pounds, the Petrel UL 10 is an outstanding ultralight sleeping bag, given its 10°F rating and premium 950+ fill-power down.

The Medium weighs 1 lb 15.6 oz (895 g), which is remarkable for a women’s 10°F sleeping bag with 950+ fill-power goose down.

The packed size is approximately 11 liters. It takes me under 3 minutes to stuff it into the stuff bag. Opening the zipper before stuffing it makes stuffing it in its bag much easier.

FF Petrel UL 10 Materials and Construction

The Petrel UL 10 is made of premium materials throughout.

The Pertex Quantum Pro shell fabric provides lightweight protection, while the Pertex Diamond Fuse lining in the footbox adds extra durability in an area that can receive a lot of wear.

The 950+ fill power goose down creates incredible loft while keeping the weight low, but my favorite part is how cozy this bag feels. It’s like slipping into a warm little cocoon, and I love being inside it.

The trapezoidal footbox design allows your feet to rest naturally without compressing the insulation.

It’s still early days, but so far, I have not experienced any noticeable down leakage.

My Feathered Friends Customer Service Experience

I had an issue with the footbox zipper: it got stuck, cross-threaded, I guess, with one side hanging lower than the other, which completely jammed it. I tried daily for a week, but it wouldn’t budge, and I didn’t want to force it and risk breaking it.

So I reached out to Feathered Friends customer service via email and included a video of my issue. They responded the same day with a few troubleshooting suggestions to try, and asked that I get back to them if it didn’t work, for next steps.

Thankfully, the suggestions worked, and I was able to fix the zipper myself without having to send the bag back.

This experience showed me that their customer support is as solid as their gear.

Feathered Friends Petrel UL 10 Sleeping Bag Pros and Cons

Who Is the Feathered Friends Petrel UL 10 Sleeping Bag For?

In my opinion, the Feathered Friends Petrel UL 10 is ideal for those who:

• Prefer a women-specific sleeping bag design
• Sleep cold and want extra warmth
• Want a lightweight sleeping bag without sacrificing comfort
• Backpack in cooler mountain environments
• Value premium materials and craftsmanship

If you prefer a wider cut around the shoulders and elbows, the Feathered Friends Lark UL 10 may be a better option.

Frequently Asked Questions about FF Petrel UL 10 Sleeping Bag

Is the Feathered Friends Petrel UL 10 worth the price?

Yes, I think the Feathered Friends Petrel UL 10 is worth its price because it is ultralight and provides a great warmth-to-weight ratio. It’s super comfortable and quiet to sleep in, and it will last for years to come.

What size Feathered Friends Petrel UL 10 should I buy?

For the Feathered Friends Petrel UL 10 Sleeping Bag, Feathered Friends lists the Small for an ideal sleeper height of 5’3″ (160 cm) and the Medium for 5’9″ (175 cm). If you’re around 5’4″ or 5’5″, you can most likely fit the Small, but if you’re unsure, Feathered Friends customer service is super helpful with sizing. I’m 5’10” and chose the Medium, which fits me perfectly.

Can you use the Petrel UL 10 in summer?

Yes. I’ve used the Feathered Friends Petrel UL 10 Sleeping Bag on summer nights in the 40s and 50s°F, and I was very warm. On the warmer nights, I slept with the zipper fully open and used the provided clip to secure the bag around my neck. This let me keep the sleeping bag over me while getting plenty of ventilation, so I stayed comfortable without getting too hot or too cold.

Is the Feathered Friends Petrel UL 10 waterproof?

No. The Feathered Friends Petrel UL 10 Sleeping Bag is not waterproof, but its Pertex Quantum Pro shell is water-resistant and breathable. The shell also has a durable water repellent (DWR) finish, which helps prevent moisture from soaking into the sleeping bag. This makes it better suited to condensation, light moisture, and damp conditions than a non-water-resistant shell, but it should still be protected from sustained rain or heavy moisture.

Final Thoughts on the Feathered Friends Petrel UL 10 Sleeping Bag

After using the Feathered Friends Petrel UL 10 throughout the Sierra, I’m really happy with my choice. What stands out most is how comfortable, warm, and protective it feels, yet lightweight enough for backpacking. The women-specific fit, temperature-control options, and premium materials make it feel like a sleeping bag designed for real adventures rather than just for chasing the lowest possible weight.

I chose warmth over saving ~4 ounces, and that was absolutely the right decision for me.

I’m looking forward to using it in colder conditions later on this year, but based on my experience so far, the Feathered Friends Petrel UL 10 has earned a permanent spot in my backpacking and car camping gear lineup.