Sinking-4 (沉-4, or Chen-4) bottom mine is a small naval mine with none contact fuses, and it is jointly developed by the 710th Research Institute and the Eastern Wind Instrumentation Factory (东风仪表厂).
Sinking-4 (沉-4, or Chen-4) bottom mine is a small naval mine with non-contact fuses. It is jointly developed by the 710th Research Institute and the Eastern Wind Instrumentation Factory (东风仪表厂).