BMA II. The BMA II mine was designed for laying without parachute from an altitude of 8,000 ft., or from S-boats. The induction coils were wound with aluminum wire, and the resistance of one coil was approximately 15 ohms. The self-incuctance ot the coil-system is 25 Henry. Each coil-rod was covered with rubber (Oppanol), and the main charge poured into the mine-case around it. The BMA II mine case is very similar in de-sign to the BM 1000 I.