The Halo Chest Seals are designed to prevent tension pneumothorax. This durable chest seal is intuitive to use and features a highly adhesive hydrogel that sticks well to warm, cold, bloody, and soiled skin in both cold and warm weather conditions. The Halo Chest Seal has an oval shape for better adhesion, even on the contours of the chest. It includes a large 'pull tab' for repositioning or 'burping.' Sizing tests have shown that the dimensions of the Halo Chest Seal represent the minimum size for optimal adhesion results. The packaging has notches on all four sides, is tear and puncture-resistant, and is impermeable to liquids, moisture, or gases."