How to Read a Dog Jacket Spec Sheet Without Getting Fooled

A spec sheet looks like the most honest page in outdoor retail. It is all numbers, and numbers feel like they cannot lie. But a spec sheet is a marketing document wearing a lab coat, and every figure on it was chosen, framed, and rounded by someone who wants the click. The numbers are still worth reading. You just have to know what each one actually measures, what it conveniently leaves out, and which follow-up question it hopes you never ask. Our guide to choosing a layer ranks the decisions; this one decodes the numbers behind them. Here are the five spec families you will meet, and the one spec no sheet can print.

Fabric numbers: denier, fabric weight, and the weave between them

Denier is the number you will see first, usually written as 20D or 70D. It describes the thickness of the individual yarns, and lower is lighter while higher is tougher. It is useful, but it says nothing about the weave, the coating, or how the whole fabric was finished. A well-built lower-denier ripstop can outlast a poorly finished heavier one. Treat denier as one input, not a verdict.

Fabric weight is the more complete number, printed as oz/yd² or gsm. Where denier measures a single yarn, fabric weight measures the finished textile: yarns, weave density, and every coating applied afterward. Two fabrics at the same denier can land at very different weights depending on how tightly they are woven and what was impregnated or laminated onto them, which is why a 20D fabric at 1.4 oz/yd² and a 20D fabric at 1.1 oz/yd² are not the same material wearing different labels. When a sheet lists denier but not fabric weight, it is telling you about one thread and staying quiet about the cloth.

The weave is the third piece, and ripstop is the word to look for. A ripstop grid interlaces heavier reinforcing yarns at regular intervals, so a tear that would run through a plain weave hits a checkpoint and stops. This is the mechanism behind the denier caveat above: a 20D ripstop can shrug off the deadfall and scree that open up a heavier plain weave, because tear strength lives in the structure, not just the yarn. Puncture and tear are different failures, and the weave governs the one that actually kills garments on trail.

Read denier, fabric weight, and weave together, because any one of them alone can be made to flatter almost any fabric.

Water numbers: hydrostatic head and the words around it

Hydrostatic head is a millimeter measurement of how much water pressure a fabric resists before it leaks, and it is genuinely useful for comparing rain protection. It is also easy to inflate and hard to verify from the outside. Test standards differ, brands test fresh fabric rather than fabric that has been flexed and abraded for a season, and nobody prints the number the garment would post after 100 trail miles. When you see a large millimeter figure with no context, ask how it was tested and whether the seams and finish live up to it.

The vocabulary around the number matters as much as the number itself. Waterproof means the fabric construction blocks liquid water outright, whether a membrane, a coating, or an impregnation is doing the work. Water-resistant means the fabric sheds light precipitation for a limited time and then wets through. A DWR finish is neither: durable water repellent is a surface treatment that makes water bead and roll off, and it wears away with use. It is a finish on a fabric, not a waterproof rating, and spec sheets blur the two constantly. We wrote a full explainer in what DWR actually is. On our own line the distinction is concrete: the Traverse Shell is waterproof and windproof because silicone is impregnated through the silpoly fabric itself, so it carries no DWR finish at all, while the Traverse Puffy carries a DWR finish over its recycled ripstop shell and trades absolute weather blocking for better breathability.

Then there are the seams, which is where a fabric number goes to be tested honestly. Hydrostatic head is measured on an unbroken swatch, and a garment is not an unbroken swatch. Every seam is a line of needle holes, and how a maker handles them — where the seams are placed, how they are stitched, and whether they are sealed or taped — decides how much of the swatch number the finished garment ever delivers in sustained rain. We broke down the methods and tradeoffs in seam sealing, explained. A large rating over untreated seams in the wrong places can wet through at pressure points long before the fabric itself gives up.

Trust the millimeter number only as far as the test method, the finish, and the seams standing behind it.

Insulation numbers: fill weight is not warmth

Fill weight, printed as g/m², tells you how many grams of insulation sit in each square meter of the garment. It does not tell you how warm the garment is. Warmth comes from loft — the thickness of still, trapped air the fill maintains — and two fills at an identical 100 g/m² can trap meaningfully different amounts of it. Mass is what the sheet can weigh. Air is what keeps the animal warm. The number measures the first and implies the second, and the implication is where the marketing lives.

The question a spec sheet answers least willingly is what the fill does when it gets wet, and for a working dog it is the question that matters most. Wet arrives constantly out there: rain, snow, creek crossings, wet brush draping over the trail. Down collapses when it soaks, losing the loft that was doing all the insulating. Synthetic fill keeps trapping air when damp and dries faster. We laid out the full comparison in synthetic insulation versus down for dogs; the short version is that a fill's dry performance is an optimistic ceiling, and its wet behavior is the floor you actually stand on.

Within synthetics, construction matters too. Short-staple fills are loose clusters of chopped fibers, warm at first but prone to shifting and clumping into cold spots over time. Continuous-filament fills like Climashield run each strand unbroken through the insulation, so the fill resists migrating, holds its loft when wet, and keeps its structure across seasons of compression. That behavior is why we build the Traverse Puffy around Climashield rather than around a bigger number on the fill-weight line.

Judge insulation by the loft a fill holds, wet or dry, not by the grams stuffed into it.

Garment weight and packed size: a performance spec, not trivia

Garment weight usually sits at the bottom of the sheet like an afterthought, and it is one of the most consequential numbers on the page. Every ounce is carried uphill by the animal wearing it, stride after stride, for every mile of the day. And when the weather clears and the layer comes off, the same ounces move into your pack and become your problem. A layer's weight is a performance spec exactly like its waterproofing, because a piece that is too heavy to bring stops protecting anyone at the trailhead.

The frame we use is warmth per ounce and protection per ounce. A heavy layer that is warm is easy to build, and always has been. A light layer that still blocks wind or holds loft is the actual engineering problem, and it is the reason low-weight fabrics and efficient fills cost what they do. This is not a preference we hold loosely. The principle the whole line answers to is the mission itself: if it's not worth the weight, it's not worth making.

Interrogate the weight the same way you interrogate the water numbers. A weight with no size attached is an advertisement, because brands habitually weigh the smallest size and let you assume the number holds across the run. Ask which size was weighed. Packed size deserves the same skepticism: compressed by whom, into what, and does the loft come back afterward. An honest sheet ties every physical number to a named size.

Treat weight as a number you shop on, and make every sheet tell you which size it weighed.

The claims that deserve a second question

"Recycled" with no number after it is the softest claim in the catalog. Recycled what, and how much of it: the trim, the lining, or the whole face fabric? A real claim names a percentage and points to a standard someone else audits, such as the Global Recycled Standard, which verifies recycled content through the supply chain rather than taking the brand's word for it. An unqualified "recycled" or "eco-friendly" on a hangtag is decoration until a number and a paper trail show up behind it.

Here is our own math, stated plainly so you can hold us to it: at least 50% recycled fabric across the line, with two exceptions we name rather than bury. The Traverse Puffy's fill is virgin synthetic, because recycled synthetic insulations exist on the market but are not yet available to a maker at our scale, and we will move to one as we grow. And the solid-colored Shell outer fabric is not recycled. The rest of the reasoning is in recycled fabrics in dog gear.

The same interrogation works on the rest of the adjective family. "Durable" with no denier, weave, or fabric weight behind it is a mood. "All-weather" is a contradiction, because weather is plural and a single layer is not. "Waterproof" with no mention of seams is a swatch talking, not a garment. None of these words are lies, exactly. They are invitations to stop reading, and a sheet that means them will always survive the follow-up question.

An honest claim names its numbers and its exceptions, and a marketing claim hopes you never ask.

The spec no sheet can print

The last thing a spec sheet cannot show you is fit, and fit decides whether any of the fabric science reaches your trail partner. A collar that gaps feeds wind straight to the chest, where a lean dog loses heat fastest. Coverage that stops short of the last rib leaves the loin bare to everything the hydrostatic head number was supposed to stop. A hem that droops fouls the gait, and a cut that binds at the shoulder gets the whole layer left at the trailhead. Every number above is conditional on the garment actually sitting on the body it was bought for.

So finish your reading with a tape measure. Chest girth at the deepest point of the ribcage, back length from the base of the neck to the base of the tail, and neck circumference. Those three numbers outrank any breed label, and how to measure your trail partner walks through taking them; our size guide translates them into a size. We build the Traverse series in set sizes with multiple adjustment points, because a dog is not a standard size and a fixed silhouette fits almost nobody well. The measurements tell you which size to start from, and the adjustment points do the rest.

And this is where we land on spec sheets generally, including our own. We would rather tell you plainly what a fabric is built to do — block wind, shed sustained rain, hold loft when soaked — than publish a lab number we cannot stand behind. Gear earns its place in the pack, or it doesn't go, and the same standard applies to every claim we print about it.

Read the numbers, ask the follow-up questions, and then put the sheet down and fit the animal in front of you.

Adventure On.