That multiple products are put into the entrance of shrinker might cause jam and fire.

放入吸塑机入口的产品个数太多时，可能因内部堵塞而造成火灾。

youdao

Like many Moscow apartments, it did not look much from the outside - a heavy, grey-steel security door, a scruffy communal entrance hall, a grand old staircase with a cast-iron banister spoiled by multiple layers of shiny, off-blue institutional paint.

BBC: In Moscow, history is everywhere