These hemming clips are used for making drapes where there are long sides and bottom hems and a lot of measuring. These help cut down on time consuming measuring and pinning. Compared to plastic ones, these stainless steel hemming clips perform much better, they lay flat and you can press and stream right over them because they are metal .They make measuring and pinning for hemming much faster, easier and more accurate. Having a set of 20 allows you to prepare 2 dresses at a time for pinning, when you have 4 dresses to hem that saves a lot of time and effort