Pink Insertion Lace, 5 inches wide plus selvage, sold by the yard, Vintage
Vintage insertion lace in a lovely pink. There are 5 usable inches plus the selvage for insertion. No stretch
In my Oh-so-distant youth, this was often used it make long full skirts, using it between solid strips of fabric. Also on crinolines (what's that?, right), slips & night gowns.
Insertion laces have no fancy finished edges, the edges are meant to be sandwiched between two other fabrics or with one & then top stitched out of sight.
Today you might use them to insert in jean legs, down the back of a blouse or in much costuming.