Bigger, better and stronger... what more could you want in a flask? The inner lining has been expanded to become more durable and dishwasher safe with an improved stopper making it leak-proof so you need not have any fears on spillages in your rucksack.18/8 stainless steel double-wall vacuum insulation, naturally BPA freeLeakproof and packableInsulated lid doubles as a cupDishwasher safe24 hours' hot24 hours' cold5 days iced