This thin and lightweight vest from Alumilire should be worn over undergarments. It contains far-infrared rays, so it's warm. Unisex. Perfect for overcoming the cold and preventing chills. Far-infrared ray products are usually expensive, but this is a bargain. 《Size》 Marked as LL, measured flat (Fits a size 15 perfectly) Length: Front approx. 60cm Back approx. 65cm Bust: 45cm (from armpit to armpit) (There is 8cm wide elastic on both sides under the armpits, but this is not included in the measurement. There is some give due to the elastic.) The front is closed with nylon magnets instead of buttons. This thin and lightweight vest should be worn over undergarments. It contains far-infrared rays, so it's warm.