Door Hardware terminology can become a bit confusing! Especially when making sure your handles will either fit existing holes or existing spaces.
Below we provide a basic guide on some key terms to help you understand the different options.
Roses (or Rosettes)
The found plate behind the door lever. Generally these cover the inner springs attached to the door, or those springs are located within then rose itself. These generally come in 2 sizes, 52mm and 63mm in diameter. This is to cater for holes in your door from 20mm through to 54mm and anywhere in between.
This is the component which moves downward to engage the tube latch or mortise, to open then door
The Tubular Latch is a closing device used on doors. It is installed in the door and can either be for doors where there is no lock, or have a locking pin/snib where you need to lock the door, i.e. in a bathroom
The metal plate installed on the door jamb. The striker holds the door latch (from the tube latch) in place and also ensures the latch doesn't come into contact with the door jamb
The Backset is the distance between the edge of the door and the middle of the hole drilled through the side of the door. This is critical in ensuring you have the correct tube latch, especially if you already have holes drilled. Most backsets on passage and privacy doors are 60mm
The spindle connects the 2 door handles on each side of the door to eachother and fits through the tube latch. So when you turn the lever, the lever rotates the spindle, which engages the tube latch. They come in all types, from split spindles to rotating ones, depending on the function of the door handle.