The plotter consists of: a base grid with concentric circles marked from 2 to 12; a rotatable perspex compass grid, marked 0-360 in degrees; an aluminium ring (fixed), marked 0-360 with 'SHIPS HEAD' at the top (0 degrees); two arms, each with a sliding cursor; a parallel rule that rotates around the centre, with a scale from 0 to 28 by 0.1 along the movable rule. Below is a table with speeds from 3 to 30 knots along the top and the equivalent miles travelled in given times (5, 10, 20 and 30 mins) in the table. At the top of the instrument is the inscription: 'DAVIES-HALL RADAR STATION POINTER / A KELVIN-HUGHES PRODUCT'. The instrument is mounted on perspex and onto a wooden board.