These super-insulated sports bottles come with an internal mesh filter to stop ice or tea leaves from coming out during use. They are perfect for hot or cold filling. Double-walled stainless steel insures that the bottle does not sweat and does not contain harmful chemicals like Bisphenol-A (BPA). Kevin Brodwick, Founder of Thinkbaby and Thinksport, told TDmonthly, "The thinksport bottle is the best priced and most functional insulated bottle on the market."