If you have been night diving or in a low light situation (Wreck or Cave Penetration) and wanted to write something down you need three hands, one for your slate, one for the pencil and a third for the dive light. This 4" x 6" Glow in the Dark Slate comes with an easily replaceable pencil with pencil clip to keep it from dangling and two attachment points so you can use it with a split ring, lanyard or clip. With this slate, you can actually see what you are writing in the dark.