The perfect baselayer for providing head to toe warmth for alpine approaches to backcountry tours. The Coefficient LT One Piece features Polartec® Power Grid® fleece which combines thermal retention with increased wicking and added breathability.
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We trust what we make because we use what we make. All Black Diamond soft goods are warrantied against defects in materials and construction for the practical lifetime of the product.
At Black Diamond, we're committed to going deep, whether that's into the mountains, the design process, or the community we love. Our fall/winter collection of equipment and apparel is built for the experience of casting off, and diving into the deep end of adventure.
Overall rating: 3.4285715 / 5 from 14 reviews.
Review topics: ["fit","quality","material","pockets","feel","layer","zipper","suit","sleeves","hoody"].
"Start with the good: This is a cozy base layer. The material feels good, and wasn't too stinky after 4 days in a row of skiing hard. The butt flap makes it easy to take a #2. At 170# and 6'1 the Medium fits me. The arms, legs, and torso are all pretty forgiving in length but not baggy. With the hood on I don't feel like the crotch is getting pulled up into my junk. The bad: The back flap feels like I'm wearing a crop top . You can tuck it in - kind of, but don't bend over or it will untuck. The elastic around the back is pretty loose on me (32" waste). I think tightening up that waist/ elastic and lengthening the back by a couple inches (so it can stay tucked in) would make this 2 star a 5."
"Buy it for winter activities. Keep me warm and very convenient"
"Good quality material and the chest and legs fit well, but I would've greatly appreciated an additional inch or two of fabric on the back panel to cover the bum a bit better. If you are on the taller side with a narrow waist, but a large chest, you'll find that the rubber piece of the lower doesnt stay in place, and the back piece leaves your lumbar exposed to the cold. I havent field tested it, but I don't think I will."
"The material is comfortable, and it keeps me warm during outdoor activities. The fit is great, and it stretches well with movement, making it ideal for layering. For my use, I would have preferred a design without the opening in the back. Otherwise, it’s a solid, high-quality baselayer that performs well in the cold."
"Been seeking a one piece base layer like this for years. Only way to roll in the deep snow. Will be buying a second one. Thank you BD for making this product and please keep them coming."
"Fantastic overall - one of the first baselayers that I’ve found to actually do its job well. IMO, drying fast is the #1 priority for a piece like this, and it does a great job. On a multi-day splitboard trip it keeps me warm, and by the time I set up camp, it was always dry. Pros: 1. Truly feels like a second skin 2. Good amount of warmth 3. Dried very quickly 4. Zippers are very smooth Cons: 1. Back flap - like others have said I wish this was just a few inches longer! It was never an issue, but it was mildly annoying. High waisted pants or bibs solve the issue entirely, but not a perfect design on the length. 2. Chaffing - I’m used to wearing merino baselayers and this feels very soft as well HOWEVER the grid-type fleece definitely gave some nipple chafing with no shirt under. Not a crisis, but not ideal. 3. Getting it off - it’s easy to get on, but I feel like I’m trying to get out of a wetsuit when I’m taking it off! Overall 4/5 - does its job fantastically, but with a few small annoyances."
"The zip to get in is a bit short. So getting in isn’t so hard. But getting out is harder than it should be. Wear any paper thin wool baselayer under it and the extra friction really slows down taking it off. Prob just a matter of time before I’m pulling the sleeve to slide it off my paltry old man shoulders and will tear the sleeve off. And the flap… oh god. I sometimes wear this snow biking. Always in the dark, chilly Colorado nights. The entirety of the winter world likes to sweep in under the tail of nearly all my jackets/coats and sweep across the thin layers left exposed by this too short flap. I pull this thing on w/ high hopes. And each time wish it was better."
"I was hoping for a hooded onsy to eliminate a baklava. Didn't provide very could neck and face shield. Had to wear an under shirt to reduce cold air rushing into the back flap. Had I been wearing pants instead of a bib, it would have been perfect access for snow down the back side. It's comfy but not what I was hoping it would be."
"Eliminate the butt flap opening and make an actual one piece base layer. The material is awesome and the hood and everything fit great but it just leaves this big awkward hole behind your back. I really want to wear this thing but I can't."
"Enjoyed the head to ankle warmth that it provided while i was out on the mountain. Low profile with solid maneuverability, i even forgot i was wearing a adult onesie the whole time. The one downfall i do have is my lower back felt exposed to the cold due to the butt flap or back of the shirt not being long enough to be tucked. Small complaint but definitely worth every penny i spent."
| Size | Chest | Hip | Arm Length |
|---|---|---|---|
| XS | 34 - 35.5 in 86.5 - 90 cm | 33.5 - 35 in 85 - 89 cm | 33.5 in 85 cm |
| S | 36 - 38 in 91 - 96.5 cm | 35.5 - 37.5 in 90 - 95.5 cm | 33.5 in 85 cm |
| M | 38.5 - 41 in 97.5 - 104 cm | 38 - 40.5 in 96.5 - 103 cm | 34 in 86.5 cm |
| L | 41.5 - 44.5 in 105 - 113 cm | 41 - 44 in 104 - 112 cm | 34 in 86.5 cm |
| XL | 45 - 48.5 in 114 - 123 cm | 44.5 - 48 in 113 - 122 cm | 34.5 in 87.5 cm |
Designed to fit slim to the body for an athletic, low-profile fit without restricting mobility and accommodating base layers or light midlayers.
A classic universal fit with comfortable ease. May feature slight body shaping, but predominantly straighter fit that will accommodate midlayers more comfortably.
Generous through the body for a casual loose-to-oversized fit without shaping. Designed for comfort, it accommodates heavier mid-layers.
Measure around the chest/bust just under the arms and across the shoulder blades.
Measure from the center back of the neck, across the shoulder, and down the arm to the wrist.
Measure around the widest point of the hips.
Measure around the narrowest part of the waist.
