Beijing Time Frequency Tech Co, Ltd. Beijing, China General Inquiries Room 11D, Zone A Office Building No 2, Jinyuan Century Business Center, Haidian District, 100097 Beijing China Acoustic control systems Acoustic Positioning Systems Acoustic Telemetry Systems Echosounder - multibeam Echosounder - single-beam Hydrographic systems Sonar - sidescan Sonar - single-beam Subbottom profiler Wet chemical analyzers Contact