SOLID Crystal Door Knobs COBALT BLUE - Don't confuse these precious real crystal knobs for a hollow glass knob. They are very heavy, including solid heavy brass fittings, and include all hardware necessary for mounting. If you can find these rare beauties elsewhere, don't be surprised to see them priced well over $100 each, but they are very hard to find. The crystal part only measures 2 5/8" wide x 1 1/2" deep. The standard overall length of the entire unit is 7" and it is adjustable to fit thicker doors to 7 1/2".
BACK-SET INSTRUCTIONS

In the U.S. there are two common back-sets for residential door locks, 2-3/8" and 2-3/4". The lock-set is the distance from the edge of the door to the center of the 2-1/8" bore hole.
These knob sets do not have latch hardware for exactly this reason. The customers use their existing latch hardware when replacing their knobs and so back-set size is not an issue for them. If by chance they have older hardware of non standard size, their local hardware store can easily supply a standard size latch of the proper length.
The inside plate with the holes are screwed in and come out. At first, the inside plates seem to keep on turning without coming off.
You have to remove the plates, install the screws with the plates, then install the handle. A little more confusing than the standard ones.
Also the 5/16 rod (handle to handle) can be too long (3/8 ) and may need to be cut and re-ground.