3,110. What Shaatnez is Permitted?

Hilchos Kilayim 10:18

One may not wear shaatnez briefly, nor on top of ten other garments, which prevents him from benefiting from it. It is even prohibited to wear shaatnez just to pass through customs (to avoid paying duty on it). One who wears shaatnez in such a case is liable to the penalty of lashes.

Hilchos Kilayim 10:19

The prohibition against shaatnez only applies to clothes that provide warmth, like shirts, hats, pants, belts, dresses, shorts, gloves, etc. However, mesh belts that people make in their pockets to hold money or spices are permitted, as is the cloth on which one places a bandage, a plaster or a dressing. Even though these things touch the skin, they’re not worn in the way people warm themselves.