VACUUM INSULATED DESIGN: The innovative double-walled insulation keeps hot drinks hot for up to 8 hours, or cold drinks cold for up to 24 hours! LEAKPROOF: The flask’s airtight lid is designed to completely prevent spills. Serving from your flask is as easy as pushing the button on top of the lid. UNBREAKABLE DESIGN: Unlike plastic or glass flasks, the Pioneer Flask’s sturdy design prevents it from breaking when dropped. ECO-FRIENDLY: Pioneer Flasks are a perfect environmentally friendly substitute for disposable coffee cups and can be used time and time again. SIZE: The flask will hold up to 500ml of fluid, with 350ml and 1 litre sizes also available.