Nested Bean Zen Sack Classic Cotton TOG 0.5 Stardust Grey 0-6 Months In excellent preowned condition. No flaws. Our weighted sleep sack is Scientifically designed for self-soothing and sounder sleep. The gently weighted Zen Sack Classic calms like your embrace by providing comforting pressure only where babies are naturally held. This secure feeling eases the swaddle transition and helps babies self-soothe through sleep disruptions, leading to deeper periods of sleep that are essential for healthy development