Solid plain sleep cap it's made of bamboo fibers that are soft and luxurious as they are strong and durable. This eco-friendly fabric is naturally porous, means it absorbs moisture better than other fabrics and dries quickly. Moisture is instantly wicked away from the scalp, so bamboo doesn’t have the potential to irritate sensitive or allergy-prone skin like some fabrics. Because of its natural antibacterial properties, headwear and apparel made of bamboo stays fresh longer. Bamboo hats and caps keep your head cool in the summer and warm in the winter.