This is the new Heckler & Koch MP5 A3 GBB with a steel stamp body.

Details:
Model: Heckler & Koch MP5 A3 GBB
Caliber: 6 mm BB
Function: Gas Blow Back
Magazine: 30 shots
Energy: approximate 1,35 Joule
Length: 49,5 - 65,5 cm
Weight: 2995 g
Feature(s): HopUp; Single Action; Steel Stamp Body; Blow Back
Age:free from 18 years, proof of age required