Our Compression Packing Bags remove excess air from bulky garments, saving up to 90% packing space! Each pack comes with 12 bags, 4 small, 4 medium and 4 large, so you can pack anything from undergarments to heavy winter coats. Also perfect for those piles of laundry on your trip back home, and for storing bulky clothes in your closet. These bags are designed so that air can go out, but can't get back in when sealed. So no vacuum is necessary!