Geophone, sectioned, c.1955
1955
MP 8 swamp and marine geophone, 21x5 diam cm
GAA reflection geophone
1950
Swamp geophone
1960
Two GS 11D geophones, 1960-76, (one incomplete)
1960-1976
Two GZW swamp geophones to BP's design made by ETEI Ltd
1960
EVP 7 geophone by Electrotech, 1956-60. 17x17x5 cm
1956-1960
Swamp or marine geophone
Three GAD swamp geophones
1950
Two GDA or GDC geophones
1950-1953