Merino Sauna Hat

The oldest piece of sauna equipment there is, and the one most people laugh at until they wear one.

Felted wool is a poor conductor of heat. Worn in a hot room it holds your scalp and ears a few degrees off the air around them, so the heat lands on your body, where you want it, instead of your head, where it drives you out early. That is the whole idea, and it has been the idea for a few hundred years.

This one is pressed from 100 percent natural merino wool, three millimeters thick, about an eighth of an inch. Merino felts finer and softer than the coarse wool in a cheap banya hat, so it sits on your head without scratching. The density does the work: it insulates dry, breathes as it warms, and takes up sweat at the brow instead of letting it run into your eyes.

The shape is the traditional cone, cut with a scalloped brim and a loop at the crown so it hangs on a peg between sessions. Dense felt holds that shape through round after round. It also crushes flat into a bag and springs back, which matters if your sauna is at the gym or on a trailer. Wool is naturally odor resistant. Air it out after a round and it stays fresh through a season of use.

• 100 percent natural merino wool felt, 1/8 in (3 mm) thick
• Traditional cone shape, scalloped brim, hanging loop at the crown
• Insulates the scalp and ears through a full round of heat
• Absorbs sweat at the brow and holds its shape
• Packs flat and recovers, easy to carry
• Naturally odor resistant, airs dry between sessions
• One adult size