Over 20 million Cool Nights® PJs sold. Upgrade that old T-shirt you still sleep in with our super-soft, super-roomy tunic tee. Details Short sleeves Cool Nights® is made with lightweight rayon fibers that stay cool-to-the-touch and keep the fabric from sticking to your body. High-low hemline 93% Rayon, 7% Spandex. Machine wash cold.