The stamp sheetlet was originally packaged as 100, with a serial number on it, and a packaging strip and plastic film on the outside. At the time of postal distribution, in order to prevent integrated sales, some processing will be done on the outer packaging, which usually includes deduction and knife processing. Button number is to button the number on it, and the knife is broken by gently cutting it on the film. Now the big version is also a broken version, and it has been cut and torn, which is also to reduce the survival of the big version.
See the knife in the picture.