Over 20 million Cool Nights® PJs sold. No sleep collection is complete without a classic v-neck tank—this one will keep you cool for a great night's sleep. Details V-neck 25" on body Cool Nights® is made with lightweight rayon fibers that stay cool-to-the-touch and keep the fabric from sticking to your body. 93% Rayon, 7% Spandex. Machine wash cold.