Wireless door chime V008B from China is very easy to install. It doesn't need professionals and special tools for installation. There is no need to set the line or to excavate a hole. It can be installed by anyone and anywhere you want.
 
Installation guide

1. Please use the good quality alkaline battery for doorbells. Don't use the the bad quality heavy duty battery
2. Don't install this product in the sunny or rainy place
3. please keep some distance between this product and the metal when you install in case it affects the usage
4. The sender and the receiver use the same codes to match with each other. Please check whether the computer barcodes on the their shells are the same or not when you buy