The Umarex gas blowback MP5 SD3 has full proper licensing between Umarex and H&K, built by VFC means that the weapons design and markings are spot on.
The 30 round real cap magazines have a very steep double stack make jams unlikely, if feeds Top / Green / Propane gas which affords the weapon about 440 FPS with 0.2g. The gas reservoir is more than enough to cope with the cool down whilst emptying the magazine in either rapid or full auto fire.
The hand grip and stock and modeled exactly after the real thing which gives this weapon unparalleled realistic feel. The main body and magazine are metal but the lower receiver / grip is all polymer like the real thing.
This replica is 76cm with the stock extended and 66cm with the stock retracted. It's around 3kg making it almost the same weight and size as a fully loaded real thing. As a metal GBB SMG, it also weight distributes similar to the real thing as the furniture is real and metal distribution is similar.
As if it did not just look good on paper, it also kicks like the very best GBBR Airsoft guns out there. If you are big fan of MP5SD3s and are looking to get an top-of-the-line GBB model then look no further, you would be hard pressed to find a better model than this one, short of the real thing.