1960 Geotech 8700C. 65 years later

[Stephen Hammond]

Still operational and ready to go. 10Kg suspension arm, 10-30 second natural period, primary and calibration coils, airtight, waterproof enclosure - light/electric boom position sensor, electromagnetic damping.   They are so beautiful, it is almost a sin to put the cover on them and hide them in a dark place...