Charm Packs are a pack of 40-42 5"squares from a line of fabric containing 1 piece of fabric from that line usually all different . But may be 2 of the same fabric in a couple of them depending how many different fabrics there were in that line .
Layer cakes are 10" squares from a line of fabric . Contain 42 squares. Equivalent to 4 charm packs . All prints different except maybe 2 or3 may be repeats .
Jelly Rolls contain 42 2 1/2" strips from a line of fabrics .1 strip of each fabric in the line.And maybe 2-3 duplicates depending on how many fabrics were in the line .
Mini Charms are cute little 2 1/2 " squares all from the same fabric line. You will get 1 of each fabric from the line and usually 2-3 duplicates of a couple of the fabrics .