Most clothing is sold on a photograph. Here is the less glamorous information — the numbers that actually decide how a piece feels in ten years.
The only number that matters most of the time
GSM — grams per square metre — is the weight of the cloth. It is the single most useful figure on any spec sheet, and almost nobody prints it. A supermarket t-shirt is around 140 g/m². It will twist at the side seam after a dozen washes. At 180 it holds. At 220 it hangs off the shoulder instead of clinging to it.
The Odyssey Heavyweight Tee is 220 g/m² in combed ring-spun cotton. Ring-spun means the fibres are twisted finer before knitting, so the surface is smoother and stronger. Combed means the short fibres have been taken out first. Both steps cost money and neither is visible in a photograph. You notice them the first time you wash it and nothing changes.
Heavier again
The Kronos and High Peaks tees are built on Shaka Wear Max Heavyweight, 100% US cotton, cut boxy with a dropped shoulder and a thick mock-style rib collar. That collar is the part to watch. A thin collar is the first thing to go on any tee; a heavy ribbed one is the difference between a shirt you keep and a shirt that becomes a rag.
Fleece, and what cotton face means
The Laurel Quarter-Zip is a 3-end fleece at 280 g/m² — 80% cotton, 20% recycled polyester — with a smooth cotton face. Cotton face means the outside you touch and the camera sees is cotton; the loop structure behind it does the warming. The zip is YKK, which is not a flourish, it is the single component most likely to fail on a garment of this kind.
The Medusa and Double Zeus hoodies use the same principle — a 100% cotton face over a 65/35 cotton-polyester body, three-panel hood, flat drawstrings. Three panels rather than two is why the hood stands up instead of collapsing flat against your neck.
Where we use synthetics, and why
Not everything should be cotton, and we are not going to pretend otherwise. The Hippodrome Silks Shirt is recycled polyester at 100–110 g/m² because a racing-silks print needs to be featherlight and hold colour through a hot November afternoon; cotton would go heavy and the print would go dull. The Victor's Wreath Pant is a 240 g/m² knit at 93% polyester and 7% elastane because the whole point of it is that it stretches and recovers. The Parian Marble Polo is a 190 g/m² stretch jersey for the same reason — an all-over marble print needs a surface that takes ink evenly across body, collar and sleeve.
Mercerised cotton
The Essential Tees are mercerised. The cotton is held under tension in a caustic bath, which makes the fibre swell, straighten and take dye far more deeply. The result is a faint lustre, a cooler hand, and colour that holds instead of fading to a wash of grey. It is a nineteenth-century process, it adds cost, and it is the reason those tees look like what they cost.
What to ask anyone selling you clothes
Ask for the GSM. Ask whether the cotton is ring-spun. Ask what the collar and cuff rib is. If the answer is a mood board, you have learned something.