Swarovski Element - this is the Decorative Button. It is a two part piece, with prongs on the front and a snap fitting for the back. It is designed to go through fabric and be secured on the back with the snap fitting. NOTE - this is a decorative element, not a functioning button. You could embed the top part with the prongs in crystal clay ... just sayin'. You get both parts - the top and the bottom.

10mm By the each.