These items were worn under the service tunic color to make the tunic more comfortable and protect the tunic color from dirt a sweat. It is held on by the buttons that are located on the inside of the tunic color. Now you know what those buttons are for. Do note that you may have to alter one or more button on the tunic to make it fit since not all tunics are made the same way. The exact same was true for the original tunics. The size correspond to the tunic size 56 hence up to a 18" (46 cm) neck circumference. It is only $3.00 to ship this item anywhere in the US, Canada, Aus. NZ. and most of Asia and $2.00 within the EU.