Finland will sell deep sea mines to blockading Lithuania The purchase is intended to ensure the security of the republic in the Baltic Sea. "This is an important part of the country's defense, which helps ensure security in the Baltic Sea," said Lithuanian Defense Minister Roberts Kovna. A blocker is a Finnish bottom mine with a 1,000 kg warhead, installed at a depth of up to 200 meters. The payload is equipped with an integrated programmable proximity fuse, the sensors of which can be customized for specific ships.