KEEP THE GLOW ON YOU. The Open Side Sleep Sac is for all kinds of sleepers - sheet on, sheet off, half on, half off- comfort no matter your preference. With extra airflow crafted from Tan Fan's premium poly that is lightweight, breathable, non-sticky, and non-absorbent, this sleep sac is guaranteed to keep your tan on you! This sleep sac is larger than a twin size bed and has a built-in pillow protector, as well as long edges to tuck your sleep sac under mattress if you prefer!