What do all of those LETTERS and NUMBERS mean when describing a Savannah?

The 'Fs'

The 'F' stands for the Filial Generation- or the relationship of the offspring to the parent.  In the case of the Savannah it would refer to how many generations away from the Serval that the Savannah is.  For example; when a Serval and a domestic cat mate the offspring would be an 'F1' or 1 generation away from the Serval-the Serval is the offspring's father.  If an 'F1' Savannah mates with another cat, Savannah or outcross, their offspring would be an 'F2' or 2 generations away from the Serval- the Serval is the offspring's grand-father.

The 'A,B,C, SBT' Letters

These letters are used to identify how many generations of Savannah to Savannah breedings are in a particular cat's background.  If one parent is something other than a Savannah the offspring would automatically be an 'A'.  When a domestic cat mates with a Serval their offspring will always be an 'A'. 

If two 'A' Savannahs mate their offspring would be 'B' meaning that at least one grandparent was not a Savannah.

If two 'B' Savannahs mate their offspring would be 'C' meaning that both their parents and  grandparents were Savannah but at least one great grandparent was an outcross. 

If two 'C' Savannahs mate their offspring would then be 'SBT' or Stud Book Tradition which is also considered to be a pure-bred Savannah. The offspring would have three generations of Savannah to Savannah breeding.  Their parents, grandparents and great grandparents were all Savannahs.  The earliest that an SBT can be found is in an F4 Savannah. 

As soon as a Savannah is bred to another cat other than a Savannah the offspring becomes an 'A' again, even if one of the parents is for instance a 'C' Savannah the offspring would still be an 'A'.

When determining what letters and number that the offspring will have, simply progress forward alphabetically and numerically from the parent's lowest letter or number.

Some examples:

F1A X F5C= F2B Savannah (SV) Kittens

F2B X F5C= F3C SV Kittens

F3C X F5C= F4SBT SV Kittens

F4SBT X F5SBT= F5SBT SV Kittens

When deciding which kitten is best for you this information has little use unless you intend to breed or show the Savannahs.  The closer that a Savannah is to the Serval is generally indicative of the price.  When choosing your kitten it is suggested that you choose one that is within your price range and with the looks and disposition that appeal to you and your lifestyle.