TDS wet notes with 40 waterproof pages and cordura cover with small pockets. Includes graphite pencil.  Allows you to write in and out of the water. It has a loose table marked with a box for run time and to place it in outside pocket with transparent window, so the recorded times can be checked, without opening the book completely.

Underwater slate, with a special shape that fits to the wrist or forearm and allows place with other instruments without any disturb.