... is welcome 5.Packing with box 1L Double Wall Stainless Steel Vacuum FlaskStainless steel vacuum flaskDouble wall stainless steel. New design and ... ,Ni 8.0-10.5 3. Advantages of stainless steel vacuum flaska: Molding, soldering, Polishing, Packaging with 10 years’ ... : Multiple sampling to test, they are double wall, could keep hot and cold for 24hours 1L Double Wall Stainless Steel Vacuum Flask