1)duoble wall stainless steel and make vacuum 2)the body have 2 design,one of slippery surface,one of scow screw thread onbody, 1)duoble wall stainless steel and make vacuum2)the body have 2 design,one of slippery surface,one of scow screw thread onbody3)it is can spray-paint all kinds of you request and silkscreen.vacuum flask