Platter bags have 2 uses. The first use is to cover the food on the platter so that if you have to leave you food at the venue it will be still hygienic even after a solid lid has been removed saving you costs in replacing lids and the bases if the packaging is non returnable. Also they are such good quality if transportation is not an issue the platter bags can save the purchase of a lid altogether. The platter bags have self sealable/reseal able strips.