The so-called hinge specification can also be called a hinge size. The hinge specification refers to the size of the length x width x thickness after the hinge is opened. The so-called size will have units, the length and width units of the general hinge are inches, and the thickness is measured in millimeters. There are many types of hinges. The specifications of common doors and windows are 50.8*30*1, 100*60*1, 63*35*1, 101.6*76.2*2, 88.9*88.9*3, etc.