Electronic heading sensors; ultrasonic application measuring and searching machines; digital communication type remote measuring and controlling machines and instruments; computer software (including computer software which is recorded in some recorded media, including CD-ROM's and magnetic discs); depth sensors; acoustic release devices; depth control devices using electronic sensors for use in towing underwater cables; connectors for attaching depth control devices using electronic sensors for use in towing underwater cables to underwater cables; computer software for use in marine seismic surveying and position measuring; measuring apparatus and instruments; electrical communication machines and instruments; electronic machines and instruments and parts thereof

Digital readout electronic compass