Fabric: Waffle shirts come in mainly waffle-knit cotton. From there, the material gets more packed with specs, transformed into synthetic like a polyester blend if you’re looking for sweat-wicking capabilities, or wool which is naturally odor-repellent if that’s your top concern, perfect for a long day on the slopes.

Style: Choosing the thermal wear right for you depends on your needs to look a certain way as well. A can't-go-wrong crewneck style is the most popular, but you can spiff that up with a henley which is infallible for wearing solo, or a half-zip that's usually found in performance thermal shirts. The fit matters too: The tighter, the better it is for layering; the looser, the better it is for looking dapper on its own.