There are four standards for length, namely 180cm, 190cm, 200cm and 2 10cm, and the general standards for width are 90cm, 105cm and 120cm. The most commonly used size combination is 190*90 or 200* 105. Specifically, different universities are different. Generally speaking, the old dormitory in the history of the school is equipped with the former, and the new dormitory will be equipped with the size of the latter.