当今中国随着改革开放速度的加快，城市里的楼房越建越多，越长越高，而平房却越来越少。而且随着治安防范措施力度的加大，几乎所有楼房住宅的大门都具有三防功能，坚不可摧。它虽然挡住了穷凶极恶的盗贼，有时也因住户的疏忽而将主人拒之门外。许多住户都经历过因钥匙忘带而? Nowadays, with the acceleration of reform and opening up in China, more and more buildings are built in the cities, the longer and the higher the bungalows are, the fewer and fewer bungalows are. And with the vigilance of public security measures to increase, almost all the doors to residential buildings have three anti-function, indestructible. Although it blocks the most heinous thieves, sometimes because of the neglect of the owners will be the owner of the door. Many households have forgotten because of the key forgotten?