I purchased this but only used it 2-3 times before I stopped using it, so I'm putting it up for sale. It can be attached to a backpack, to your back (with a special buckle), or used on a chair, offering various ways to use it. Also, since it uses a Peltier element, it doesn't use water, making maintenance easy. The Peltier cooling plate allows you to switch between temperatures ranging from -20°C to 50°C, supporting both cooling and heating. The material is mesh for comfort. - Model Name: PM888 - Cooling Method: Peltier - Temperature Range: -20°C to 50°C - Number of Cooling Plates: 3 - Material: Mesh fabric - Features: Can be attached to the back or a backpack - All accessories and instructions are included. Thank you for looking.