1. Ultrasonic Seam Technology Sleeping bag features improved ultrasonic sealing for 30% stronger seams than traditional stitching, ensuring extended performance even in rugged outdoor conditions. Ideal for frequent outdoor enthusiasts and backpackers. 2. 515°C Temperature Control 200g faux silk cotton filling maintains ideal warmth without overheating, scientifically tested to keep you comfortable through chilly nights under the stars. Works suitably in spring/fall camping seasons. 3. CoupleFriendly Attachment System Unique zipper design allows connecting two sleeping bags within seconds, creating doublewide space for partners while blocking cold drafts. Suitable for romantic getaways or family camping trips. 4. Breathable AllSeason Fabric 240T spring satin lining wicks away perspiration while polyester twill exterior resists morning dew, providing 360° comfort whether used as a standalone bag or unfolded blanket.