Here is a guide for ordering the correct height shade carrier:
14'' shades need a 4'' carrier
16'' shades need a 5'' carrier
18'' shades need a 6'' carrier
The above is just a guide but it works for our lamps and shades together. If your lamp has a 'riser' beneath the lampholder you may need to adjust the shade carrier height.
You might also be interested in the following products