The HK45 was developed as a product improvement of the highly regarded USP45, first released in the 1995.
Umarex H&K 45CT GBB Magazine
The HK45 was designed to fit requirements of the U.S. Military JCP (Joint Combat Pistol) program which had the purpose of arming the U.S. Military with a .45 ACP semi-automatic pistol instead of the 9mm M9 pistol.
Elite Force HK45 Magazine Rebuild Kit
The Elite Force HK45 GBB Mag Rebuild Kit comes with everything you need to restore your HK45 magazine back to operable condition.