This paper mainly introduces why gate brass knocker turns green, how to clean brass door knocker and how to protect antique brass door knocker from sulfide corrosion. Read More
This paper mainly introduces the door knocker and its function, how to install it in general and how to install it without tools for decoration effect. Read More
This paper mainly introduces the design requirements of hotel room door lock, the function of hotel door lock and the self-protection method of hotel living safety. Read More