Listing is for both: Midi length petticoats can be worn alone or under a skirt/dress. The elastic is very stretchy however it can be a little tight once on. Waist 14' Stretch to about 18' but again once on its snug the elastic is very tough Note: The black one does have a slight hole where I cut the elastic to loosen it up some Comparing it to other skirts I own I would say its a L-XL