Tank tops are underestimated as a technical layer. On warmer days as a single layer it breaths like wearing nothing at all, but you’re not completely naked to the elements. In colder climates the tank top works great as a next-to-skin layer, insulating your core and allowing better breathability and range of motion to your arms. A tank top is always a good choice.
Wool because it is the gold standard in most situations. Organic because it makes a difference. Silk because it softens, strengthens, and improves wool’s temperature regulating qualities.