This size #40 button shell has a diameter of 1" before covering and is boxed with 720 rust resistant shells and 720 style 44 wire eye backs. This has a "U" shape smaller loop specially designed to prevent fabric damage and pull through in delicate material. You need the steel button cutter, covering die (Item #BMPD40), and button covering machine (Item#BMPM) to assemble this button for a professional look. This item is sold in a 5 gross box (also available in a 1 gross box).