All of the machines come with backing plates, but you may want to put a larger or smaller one on a machine you already own. These are consumables, so they will need replacing from time to time.
- Nano: 1.25" or 2"
- Mini (LHR75E), LHR75(Pneumatic), and LTA75 (Triple Action Pneumatic): 3"
- LHR15ES, LHR15MKIII, Duetto, and LTA125 (Triple Action Pneumatic): 5"
- LHR21ES, LHR21MKIII: 6"
I've been known to not follow the rules. You can experiment putting a 5" backing plate on machines designed for a 6" and vice versa.