Approximately 1.1 to 1.2 cm in diameter. This is a set of 5 back buttons. (These are change buttons for attaching the back of student uniform buttons, with a black plastic base and a cherry blossom mark.) 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, so you cannot track the package. (We also have another listing that ships via Yu-Packet Post Mini, which does offer tracking.) Delivery will be by mail slot, not hand delivery. Orders confirmed and paid for 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 on the internet for more details. * Brand new. * Free shipping.