What is the difference between D, DF, S, SG & SGX

[maddiekisses]

I've been doing my research and basically know the hive set-up I would like.  I found a company with better than average prices, but it's the only place where I have seen the frames designated as D, DF, S, SG, and SGX.  I thought all frames were interchangeable as long as you put them in the right size super.  Do I have reason to be confused or is this simpler than it seems?

Thanks

[Michael Bush]

I assume we are talking about Kelley, who offers the largest combinations of things.  Basically you can make hundreds of different combinations of the following possibilities:

Top bars:
  Split
     Thin
      Kelley's special thick ones.
  Solid
  Grooved
  Wedge
  Foundationless (A Kelley specialty)

End bars:
  Standard
  Kelley's special thick ones with grooves so the foundation just slides in the groove
  All of these, of course come in varying depths.  Kelley has the most but not all.
  Depths:
    4 1/2"
    5 1/2"
    6 1/4"
    7 1/4"
    9 1/4"
   11 1/4"

Bottom bars
  Solid
  Split
  Grooved

You can put these together in any combination for various purposes. 
Grooved top and bottom are typical for plastic foundation or putting foundation in with a wax tube fastener. 
Split (thin) top and solid bottom are typically used for cut comb.
Split (thick) top bar, grooved side bars and grooved bottom bar is a Kelley specialty to allow just sliding foundation in from the top and not needing pins for the sides.
Wedge top and split bottom is typically used for wired wax.

Kelley usually specifies exactly what foundation the frame was intended for.