Self-inflating mats are portable sleeping pads designed for camping and outdoor activities. They combine foam insulation with an air chamber, allowing them to expand and fill with air automatically when unrolled. This feature provides comfort and support while minimizing the need for manual inflation. These mats are lightweight and easy to pack, making them ideal for backpackers and campers. Many models also come with a valve system that allows users to adjust firmness by adding or releasing air. Popular brands include Therm-a-Rest and REI, which offer various sizes and thicknesses to suit different preferences.