Approximately 1.1cm in diameter. This is a set of 5 back buttons. (These are change buttons for student uniforms, with a black plastic base and a cherry blossom mark, used to fasten the buttons from the back.) Replacing the back buttons is easy, even for children. The 5 back buttons will be placed in a pouch and sent via Japan Post's Mini Letter service in simple packaging. There is no tracking number available. (We also have another listing that ships via Yu-Packet Post Mini, which does offer tracking.) Delivery will be by postal mail, not hand delivery. Items for which payment is confirmed by 12:00 PM (noon) will be shipped the same day. (There are basically no days when we cannot ship, but if there is an urgent matter that prevents us from shipping, we will ship the next day.) Depending on your region, delivery usually takes 1-3 days after the shipping date, delivered to your mailbox. Please check the estimated delivery times from Osaka for Mini Letters online for more details. * Brand new. * Free shipping.