Invented in 1913, William Stanley ensured this flask was built to last and with its double wall stainless steel insulation would keep liquids to the desired temperature for numerous hours. It is also leak proof. This 1.9 Litre Classic Green flask can keep drinks warm or cold for a full 32 hours meaning you will always have a tasty drink to hand. The heavy duty handle and lid that doubles as a cup means you can sit and have a drink practically anywhere. Due to its light weight and durability it is ideal for construction site workers.