Stainless Steel double walled and vacuum insulated, they keep drinks ice cold for 24+ hours and hot for 5+ hours. Please contact me with questions on color variations or for options not listed. These tumblers are sealed with FDA compliant, food grade, two part epoxy resin. Tumblers are made to order, hand crafted and small imperfections or differences may be present. Tumblers are hand wash only. Care instructions are provided with every tumbler. Due to the fact that these are all custom no returns or refunds if you have a problem with an order please contact me right away and I will work with you Do not see exactly what your looking for? Please contact me.