37-mm gun VK 3.7 (Flak 18), mounted under the fuselage of the German Messerschmitt Bf-110G-2/R1 twin-engine fighter of the Nazi Luftwaffe of Third Reich.
VK 3.7 gun of Messerschmitt Bf-110G-2/R1 was very effective against Allied strategic bombers, however the weight increase of the aircraft and the additional air resistance of the fairing guns worsened the performance of the Messerschmitt Bf-110 fighter, making it particularly vulnerable in combat against fighter of escort bombers.