Abstract: An insulating sack for carrying beverages and other items includes an inner fabric bag having an open mouth and a closed bottom, an outer bag connected to the inner fabric bag along said mouth, means defining a first drawstring pathway adjacent said mouth, a first drawstring inserted along said pathway and having ends extending outside of the pathway whereby the first drawstring can be tightened to purse the mouth, and a second drawstring passing circumferentially around the inner bag and inside of the outer bag, whereby the second drawstring can be tightened to reduce the effective diameter of the inner bag at a position more than halfway from the mouth to the closed bottom of the outer bag, thus enabling one to custom-fit the sack to items of various sizes.