This component is the factory-specified rear sight drum designed for the MP5K PDW and MP5K-N series of firearms. It is also a favored enhancement for numerous existing clones available in the market, as many of these clones utilize factory-inaccurate G3 rear sight bases that have been modified to resemble an MP5 sight drum. The sight system for SP5K, SP89, Z5-P, Z5-K and AP5K models to improve targeting accuracy and performance Alternative versions and personalized configurations of the software or hardware are available, including various clones and custom-built models