This is a British military issue lightweight combat jacket / long sleeve field shirt in DPM camouflage. They are made of a 65/35 cotton/polyester blend, have two chest pockets, and a button down front with lightweight zipper. These are sized in NATO sizes, the first number of the size represents the length and the second represents the chest size.
These shirts have been previously used/issued by British military and are in very good condition, showing only minor signs of use.