Germany produced hundreds of 20mm FlaK 30 light antiaircraft cannons, but these suffered from the drawback of having a relatively low rate of fire of 120 rounds per minute (rpm). One method of improving this situation was to develop the 2cm FlaK 38, which had a rate of fire of 220 rpm. However, this was still insufficient, and so Rheinmetall combined four 20mm cannons onto a single mount. The resulting weapon, known as the Flakvierling 38, then produced a practical rate of fire of 800 rpm. Produced from 1940 onwards by Mauser, the 1509kg weapon was usually operated by a crew of eight men. Of course, the 2cm Flakvierling 38 could be employed against ground targets as effectively as against low-flying aircraft too.