Warning Shell / Key Shell

This is a key accessory designed for the elderly, solitary, amnesiacs, and obsessive-compulsive disorder.
It can be mounted on a key.
When you go out but forget the lights,kitchen appliances,gas stove are turned off or not, you need to open the door to confirm it,this product can help you.
When you use your key to lock the door,you can find whether these devices are turned off.
When the corresponding lights that correspond to the device dose not turn off,you can open the door to turn off the corresponding device.