A solution means a set of hardware to be equipted to your window or door to fullfil your requirements for safety, security, ventilation or entrance, as well as convenience of operations. A solution normally contains fixing parts, locking system, and operation device. You can have a basic opening and closing function, or some additional ventilation functions, , or other restrictive functions for different purposes. HOPO will provide whatever you want for your windows and doors, and will achieve more and more amazing function for your potential requirements.