We have become dependent on our Dive Computers to the point that many divers do not even own a set of Dive Tables anymore. However, the Safe Diver always has a Backup Plan, just in case. Make sure you have a set of Dive Tables in your Save-A-Dive Kit just in case your Computer suffers some 'Technical Difficulties'. These Waterproof Dive Tables have an Easy-to-Follow Flow Chart, and U S Navy Decompression Tables to 140' (42 meters). Table is Set-Up in the basic 3 Chart Format, and is Easy-to-Follow to make Single or Repetitive Dives. Tables can be used for Imperial (feet) or Metric (meters) Dive Depth Calculations These Waterproof Plastic Tables measure 7" x 9" (17.8 x 22.9 cm) and have an Eyelet for attachment of a Lanyard.