To order a part for your Fluke meter you will need to determine the part number. Part numbers are listed in the service manual, user manual, instruction sheet, calibration manual or online knowledge base.
Here you can find the Fluke Manuals and Help center knowledge base
For example a searching the Fluke Manuals for 54 will offer:
Viewing the 51-54 Series II | Service manual will offer a replacement part section:
Sometimes you are offered a parts diagram:
Once you have identified the part you can then contact Fluke Customer Care at 800.443.5853 for price and delivery.