FunctionWhat's this?Passage: Used where doors to not need to lock. Typical usage are closets and child bedrooms.Privacy: Used where doors need to lock from the inside, but where there is no key to unlock from the outside. Typical usage are bathrooms and bedrooms.Keyed: Used where doors need to lock and where a key is needed to unlock or lock from the outside. Typical usage are entry doors or locked storage rooms.Single Dummy: Used where doors need surface mount hardware only. Typical usage are bifold closet doors or decorative only applications.Double Dummy: Same as a single dummy but with two pieces for a surface mount front and back application.Dummy Set: Used where doors need non-functional hardware but where the door is drilled out.