Perfect for placing in your Passive Cool Boxes (i.e. NOT Thermo Electric Coolers) to ensure that your food and drinks stay chilled and fresh when you are having a picnic, on a camping trip or at an outdoor event.Simply place the IcePacks in your home freezer overnightbefore you head out and this will ensure that the ice packs are completelyfrozen and fully prepared to offer your Cool Box the maximum chilling performance.Re-usable and washable Ice Packsare the essential and ideal Cool Box companion.We do not recommend that youuse with Thermo Electric Coolers.For best effectiveness use more than one ice pack.Completely re-usable.Fully Washable.Freeze for over night before using (10-12 Hours).Perfect for use in conventional Cool Boxes & Cool Boxes (i.e. NOT Thermo Electric Coolers).Keeps food & drink chilled & fresh for hours at a time.