It's made of cotton, containing a USB. The inner heating sheet wraps the whole bottle body uniformly and keeps warm without fear of milk cooling. The constant temperature is 40 C. The baby can drink milk safely. The magic stick adjustment fixed 90% of the bottles available. The inner liner can be disassembled and cleaned easily. Zipper opening design, removable inner liner and cloth cover, cleaner and sanitary. The quotation doesn't include the bottle.