There are 4 styles of backplate handles but the most common type is the Lever latch door handle on a backplate. This can be found in residential houses, commercial spaces and public buildings. Doors are fitted this handle along with a mortice latch which is used to keep the door shut. The door handle features a lever handle which is used operate this latch.
A lever on rose door handle is a type of door handle which is more mondern and contemporary than your typical lever on backplate door handle. A lever on rose door handle features a round or square rose, and can be used alone if all you require is to use a door latch opening.