Neck style bag is made so that you can wrap it around your neck. Fold in half before putting in the microwave so that it will fit. They are 20 inches long and 4-5 inches wide. They will hold the heat for approximately 1 1/2 hours. Back bag is approx. 9" X 9". My handmade corn bags are made with beautiful flannel fabric and filled with whole field corn. Corn bags are microwavable and consumer friendly. Corn is used because it is a larger grain and holds it’s heat longer. The first several uses will release a small amount of moisture as it comes out of the corn. This is normal and will disappear with use. Corn bags are the all-natural way to relieve aches and pains. I not only make them to sell, I am a dedicated user myself. I use them for back and neck aches when I need to but mostly I use them to keep my feet and other body parts warm. I warm one to take with me in the car; I use one when sitting at my desk to keep my feet warm. I put several in my bed at night to snuggle my toes into. What can I say? I’m hooked on my corn bags. Can be used for backaches, neck pain, migraines, bursitis, arthritis, insomnia, earaches, carpal tunnel syndrome, Fibromyalgia, muscle pain, headaches, sport injuries, and menstrual cramps. .