No need to wonder what size stainless steel collar stays your shirt requires, because the geniuses at Swiss Stays have created an adjustable set. Directions are printed on their clever container. Very creative! The patented adjustable stays can be adapted to fit any of the 24 dominant collar sizes. Moreover, stays can adjust create these sizes: 2", 2 1/3", 2 1/2", 2 3/4". You can see how they adjust with the additional pictures included.