The Portable USB Heating Lunch Bags are made of waterproof Oxford cloth, with automatic temperature control to heat your lunch to about 50 degrees before switching to thermal insulation mode. It is compatible with various food containers and is perfect for outdoor activities. Keep your food warm and enjoy a hot meal anytime and anywhere. Featrues 1. Magical Portable Microwave: Tired of cold and unhealthy food or waiting in line for the office microwave? Get your own lunch warmer and enjoy a hot meal conveniently by keeping this magical little oven! 2. Super Easy to Use: Portable lunch heater design with automatic temperature control, heat your lunch to about 50 degrees then it will automatically switch to thermal insulation mode, no fear of food overcooking, preserving moisture and enhancing flavor. 3. On-The-Go Kitchen Assist: This food heater is great for outdoors, camping, fishing or anywhere outside. Just choose your favorite fresh or prepared meal in advance. 4. Wide Compatibility: Portable food warmer oven is compatible with any flat bottomed food container size 16cm W x 21cm L x 8cm H, which accept glass/plastic/cardboard/metal/aluminum foil/ceramic type of container. 5. Waterproof Material: The outer layer is made of waterproof Oxford cloth, and the inner layer is aluminum foil and pearl cotton to better maintain the temperature. Specification Material: Oxford Cloth+Aluminum Foil+Pearl Cotton Color: Gray Size: 21168 cm Weight: 200g Package Include: 1 Heated Lunch Box