These leggings are a must have! If you like soft fabric that offers the most compression, this is the fabric for you. It is comprised of 90% Nylon 10% Spandex with a smooth soft finish. This fabric is going to give you that cotton-like feel. It is great for yoga, running, and other training activities. We would be careful wearing it to Hot Yoga. It may be on the heavy side for that type of warmth. Don't let the softness fool you. This fabric keeps its shape over time, very breathable, and wicks away moisture.