Heat packs are portable devices designed to provide warmth and comfort. They can be filled with various materials, such as gel, rice, or salt, and are often used to relieve muscle tension, soothe aches, or keep warm in cold weather. Some heat packs can be heated in a microwave, while others may require boiling in water. These packs come in various shapes and sizes, making them suitable for different body parts, like the back, neck, or hands. Many people use heat packs as a natural remedy for conditions like arthritis or menstrual cramps, as the heat can help improve blood circulation and relax tight muscles.