Helix current meter by Hilger & Watts Ltd
- Made:
- 1960-1965
- maker:
- Hilger and Watts Limited
Helix current meter by Hilger & Watts Ltd, successor to Mk VI acoustic meter, c 1965, marked SK70 Mk II
Helix current meter by Hilger & Watts Ltd, successor to Mk VI acoustic meter, c 1965, marked SK70 Mk II