Standard commercial school issue. 128mm square. 0-360 scale on outside edge with reverse 360-0 scale adjacent. Location letters NE, SE, SW and NW on corners.
 
Uses a 1:500,000 scale and includes 5 NM and 10 NM radius rings for quick and easy measurement. The 2 NM grid makes alignment with parallels simple.
 
With aeronautical symbol cut-outs of a square, circle and triangle. Centre drilled for location and gridded in squares of 13mm(4nm). Supplied in a self-sealing clear plastic case.