OK, let me try to clarify just a bit further:
As has been mentioned, "CAB" and "SLB" are somewhat synonymous. "CAB" stands for "Cabinet" and "SLB" stands for "Slide Lid Box". It gets confusing because both are technically Slide Lid Boxes. "Cab" is typically reserved for the 50 count box, but not always and it will depend on who you are talking to. Both are all wood boxes and are fairly un-adorned. For the record, CAB should never mean two boxes.
Where some of the confusion comes in is that there are some cigars that come in both "SLB" and "DB" or Dress Box. A perfect example would be RyJ Belicosos Finos. These come in both "DB" and "SLB". The SLB version tends to cost more as the packaging, I'm sure, costs a bit more. Further, they are more prized due to the fact that there is a common belief that cigars age better in Cabs or Slide Lid Boxes than they do in Dress Boxes.
Below, in order: 50 Count Cab of Boli PCs, 25 count SLB of Boli BF, 25 count DB of Boli BF.
Hope this helps.