This is an Ocean Themed Digraph center sort. There are 6 images per digraph (6 for ch, 6 for sh etc) and within each of those three images have beginning sound digraphs and three have ending sound digraphs (except wh,which is all beginning sound). In all there are 24 cards to sort between the digraphs Sh, Ch, Wh and Th.
In addition the sort is shark themed. Each of the clipart used on the cards for students to sort are animals that Sharks truly eat (an assortment of fish, seals and whales) so it's a good way to pull in some science in your classroom.