The Qwetch bottles are of made a high quality two layer 18/8 (304) stainless steel. They have excellent thermal properties. They come with a leak proof stainless steel lid, also made with polypropolyene (PP 5) and stainless steel inside. *Only the stainless steel comes into contact with the liquid inside the bottle.
The 260ml size will keep drinks warm up to 5 hours and cold up to 7 hours while the 500ml size will keep drinks warm up to 12 hours and cold up to 24 hours!