Stores Reference 6B/125. By H.T.A (1929) Ltd. Metal construction with sliding scale for airspeed and scales to allow for drift and distance etc. It is soiled and shows use and wear. Note that the perspex rule has broken and been glued - see photographs. Fair condition. Used by Navigators to calculate their routes. Stock code M23623.
Update : the glued repair to the perspex rule has failed in transit to a show and requires re-glueing. We have reduced the price to reflect this.