This is the Dive Rite Underwater 3 Page Wrist Slate for Scuba Diving and Snorkeling Features: Three separate writing surfaces via three leaves that flip up for easy access An elastic cord snaps the leaves back into place and a cord with sleeve stows the attached solid, carbon-stick pencil The Wrist Slate fits on the curve of the forearm and can be attached with either the Velcro strap or two small elastic cords included in the kit Dimensions: 4-inches tall x 4-inches wide (10 cm x 10 cm) Weight: 4.2-oz (0.12 kg) Use them for note taking, back up deco schedules, or as a safety communication device!