stainless steel skinny tumbler adopts double-layer vacuum heat insulation technology. Keep hot drinks for 12 hours and cold drinks for 24 hours. Vacuum technology makes the outer wall sweat-free, no matter what beverage you drink, you can keep your fingers dry and will not burn your fingers.We have not cut corners.The inner and outer walls of the 20 oz skinny tumbler all made of high-quality 304 stainless steel, free of BPA and rust. High-quality tumblers ensure your daily drinking water health.The slim insulated water tumbler is small in size, light in weight, thin and easy to hold, suitable for most car cup holders. Please call us for more info!