You will receive the 3 polished Orthoceras seen in the photo.
 
The fossils commonly known as orthoceras are extinct "straight-shelled" cephalopods that lived during the Upper Devonian period around 370 million years ago. They lived inside of their shell, had tentacles they could use to grab food and used jet propulsion, squirting water to move.

The largest is approximately 2" smallest approximately 1.75"