sorry, can u explain more, how to nullified? I going to get a security door. which the contractor told me it is very secure, got 1 set for contractor and another set for home owner. But my doubt are, for contractor and for house owner not the same set? but accessing the same door lock?

oic, thanks. last month when contractor show me this type of security door and proudly told me that this door lock got contractor & master keys. I was thinking "what the hell is this?." haha.. now i know...

Regarding the security door, anyone got good recommendation? my contractor recommended me to a puchong shop called "K2-Asia". Anyone 1 tried that be4?