This compact GPS parallel rule is well-suited for use on small chart tables. The primary purpose of the ParaLock Plotter is to enable the transfer of GPS positions rapidly, easily, and accurately to and from any paper chart. This unique plotter features three unique design concepts: 1) The black locking knob is friction adjustable for fast lat/long transfers. It enables the two rulers to be fixed in any given separation, which allows rapid determination of GPS position. 2) Two sets of finger holes enable finger tips to act as friction pads on the underlying chart and inform the navigator if the rule has slipped while plotting. 3) The ParaLock Plotter is only 7.25 inches (18.42cm) long, as opposed to the standard rule length of 15 inches (38.1cm), but its opening width is the same as standard rules. - 7-1/2 inches (19.05cm) long- Sturdy, clear acrylic for maximum chart visibility- Locking knob- Finger holes - Graduations for use as protractor to determine compass bearing- Ruler across bottom to transfer distances to mileage scale- Fits in a pocket or drawer- Plastic Storage sleeve with instructions on back- Lifetime warranty