Slate

Definition: There are many different types of slates, but the most common are fish slates and writing slates. A fish slate is a waterproof plastic sheet covered in pictures and names of fish (and other creatures) the diver is likely to see. A writing slate is a blank piece of plastic with a pencil attached by a cord and is used to communicate by writing underwater, taking notes, or drawing. Slates are normally attached to a D-Ring on the BCD.