Anti-ear-tightening adjustable mask back buckle

The utility model relates to an ear-tightening-preventing adjustable mask back buckle which effectively solves the problem that the adjusting range of a mask back buckle is limited. According to the technical scheme for solving the problems, the anti-bacterial packaging box comprises a horizontally-arranged bottom plate, the bottom plate has various shapes, a plurality of vertical limiting columns are evenly distributed on the bottom plate, a limiting protrusion is arranged at the upper end of each limiting column, arc chamfers are arranged on the edges of the bottom plate, the limiting columns and the limiting protrusions, the bottom plate is made of flexible anti-bacterial materials, and the bottom plate is made of flexible anti-bacterial materials. And the bottom plate is made of a thermosensitive material which can change color at more than 37 DEG C. The device is simple in structure, convenient to manufacture and low in cost; according to the device, through the design of the multiple limiting columns, t