Frank Green 1 Litre Ceramic Reusable Bottle. The Frank Green philosophy is to design innovative products that are stylish, functional and good for the environment. The reusable triple-walled Ceramic Bottle is designed for the modern adventurer. Its revolutionary vacuum-insulated and triple-walled stainless steel range keeps contents hot or cold for up to 10 hours. A ceramic layer allows it to deliver the pure flavour and aroma benefits of a ceramic cup, with no residual flavour - even when going from coffee to water.