Lightweight but incredibly strong” Magpul’s PMAG D-50 MP is a highly reliable” 9x19mm Parabellum” 50-round drum magazine for HK94/MP5 large-format pistols and pistol caliber carbines.It’s unique drum configuration keeps the height of the magazine manageable” allowing for prone firing and easier storage. For easy loading” it includes a ratcheting loading lever that removes tension from the internal spring. They’ve also included a rounds-remaining rear window” a high-visibility follower and a capacity indication roller.