Meaning of letters on scope.

[Speedmaster2]

What is the whole scope title ? it might mean something about the reticule or it might just be a model designation.

The only writing on the scope is IR 3-12 x 40 ARF, no manufacturers name or anything else.
I have 2 spare scopes that aren't on any rifles, one is a Hawke Fastmount 3-12 x 40 and the other is a Hawke Eclipse 3-9x 50 AOIR. The Eclipse is probably too long and too strong a magnification for the Pard so I'll maybe try the ARF one first and if it doesn't work well I'll try the Fastmount. If that doesn't work then I'll look at the other scopes on my other rifles to see if any of them will do.

[gtfreight]

I think I saw a scope on Optics Warehouse site that was advertised with variable focal plane. I wonder if it could be similar?
Edit: forget that, I've just been back on the site and can't find it. I must have been dreaming.

[Steyr]

2nd FP could be described as adjustable as the "ret adjusts when mag is altered even though it actually should remain proportionate. Probably a case of semantics. What difference does it make. The scope does what it does. Changing letters means what exactly.