Model 01Cold, on the record.
Washed linen, a cotton liner, and a pocket behind the front for a cold pack. Clean shorts just for the sauna. Leave the sweaty gym kit in your locker.
No payment today. Nothing's made yet. We'll keep saying so.
Someone online once asked how he'd explain bringing ice packs into his gym's sauna. Good question. It became line one of the spec.
The pocket sits on the front of the liner, behind the shell. The pack goes in at your locker, and after that there's nothing to explain. Designed to read as shorts from three feet away.
Known risk: felt, film and a pack add thickness at the front of a loose short. We don't know how much that shows until the first prototype is on a body. Whatever it looks like, the photo goes in the log.
Dashed lines are how engineers draw things you can't see from here. The term is "hidden lines." We didn't have to make anything up.
Most people sit in the sauna in whatever they just trained in. It's polyester, it's soaked, and everyone on the bench can tell. These stay in your bag and come out for the sauna only. Leave the sweaty gym kit in your locker.
Most gym shorts are polyester. Ours are planned in washed linen, about 130 to 200 g/m², with the exact weight picked once samples have been in a hot room. A running-short cut, a 5-inch inseam, and side splits so sitting down isn't a project.
A cotton brief-style liner is built in. A linen shell and a cotton liner against your skin, and no second pair to dry on a locker door. The waistband is 1.25-inch covered elastic with a cotton drawcord.
A pack about 4.5 by 4 inches slides in from the top and sits behind fabric. The idea is a cold spot that takes the edge off a long round, with nobody on the bench any the wiser. Or leave it empty and you've got good shorts with a quiet pocket.
Six layers, in the order the heat meets them. Keep scrolling and they come apart. The outline is the real pocket piece from pattern v0.1.
What the room sees. Washed linen, about 130 to 200 g/m². This is the part that has to look like shorts, so it does nothing clever.
The front of the pocket. It keeps the felt from showing and gives the pack a plain cotton wall to sit behind.
The insulation, on the room side and not the body side. That placement is the whole idea. It's also the part most likely to add bulk, so its thickness is still open.
Emergency-blanket film, a polyester-based material. It's there to bounce radiant heat back at the room. It sits behind the felt, away from your skin.
Soft, freezable, about 4.5 by 4 inches, sealed in plastic film. Type not chosen yet. It slides in from the top in the locker room.
Brief-style, and it holds the whole pocket. The pack sits behind fabric, never against skin. Orange bar-tacks mark the pocket corners, because a good detail should get to show off somewhere.
Heat comes from the room. Felt and film sit on that side, so the pack should spend less of itself on the sauna and more of it toward you. That's the theory. Test 003 is where it has to show up.
Safety: The pack sits behind fabric. Never put a frozen pack directly on bare skin. If you go numb, take it out. Because the insulation sends cold inward, we'll measure the skin-side surface too, starting when the pack is at its coldest.
We can't tell you it helps. We'll tell you exactly how cold it is.
Entry 000. Informal.
~15min
A bare 32°F pack in a room at about 200°F went warm in about 15 minutes. Alex tried it, nothing was controlled, and it's the one data point we have. It's also why the pocket exists.
Goal: a full round of about 15 to 20 minutes with the insulated pocket. It's a goal. The tracks stay empty until there's something measured to put on them.
Probe on the skin side, a reading every 3 minutes, four configurations, one per session. We looked and couldn't find anyone publishing a time-and-temperature test from a real sauna. At least one brand has promised one. Good. More data is the point.
That's the first thing we designed against. It's drawn to read as shorts at three feet and it gets loaded in the locker room. How well that worked is a question for the prototype, and the prototype's photos will be public.
It's free and it works for a while. It also shifts, drips and starts conversations. The pocket is meant to hold a pack in one place, out of sight, with insulation on the room side. If your towel system works, keep it. We respect a system.
You could, and that's the real alternative. It's two garments, and the outer one has already been to the gym. Ours is one garment, linen outside and cotton next to you, kept clean just for the sauna. If that doesn't matter to you, buy the boxer.
If you like yours, wear them. They just tend to be polyester, they've probably had a long day, and they don't have a pocket.
Unknown. A bare pack lasted about 15 minutes in one informal try. The goal with the pocket is a full round of about 15 to 20. The protocol is public and so is the result, once there is one.
The design goal is that nothing drips on it: a sealed pack, inside a pocket, inside a liner. It's a goal until it's tested. Sit on a towel regardless. That part's just manners.
Correct. Finland can sit naked. Your gym has a dress code.
We don't know how many people want the cold at all. That's the biggest unknown we've got, so we're asking. Either answer helps, and both get you the same shorts.
First-batch prices. No payment today. Extras: two more packs $18, a wool carrying sleeve $24. Details on the product page.
We're aiming for summer 2027. We'll confirm a real date before we take any money. A date goes here when there's a sewn prototype and a factory quote to back it up, and not before.
I'm Alex. I fell for sauna at University College Dublin, going every day after training. Now I go at a gym in Boulder.
I took a bare cold pack in once. It was warm in about 15 minutes, which looked to me like a solvable problem. So there's a drawing, and a test plan, and now this page. I'm going to show you all of it, including whatever goes wrong.
Alex
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