Mosquito FB Mk. XVIII armed with a 57mm cannon

The Mosquito FB Mk. XVIII (sometimes known as the Tsetse) was armed with a Molins "6-pounder Class M" cannon: this was a modified QF 6-pounder (57 mm) anti-tank gun fitted with an auto-loader to allow both semi- or fully automatic fire. 25 rounds were carried, with the entire installation weighing 1,580 lb (720 kg). In addition, 900 lb (410 kg) of armor was added within the engine cowlings, around the nose and under the cockpit floor to protect the engines and crew from heavily armed U-boats, the intended primary target of the Mk.XVIII.