The Tippmann M4 Recon AEG airsoft gun series with the M-Lok metal rail system.  Comes in Shorty (6 inch); black in colour

The new Recon Tippmann AEG M4 guns include standard V2 metal gearboxes, Mosfet unit, metal bearings, high-quality components (Lonex OEM), high-quality solid polymer body, and receiver (similar to the Amoeba series in feel).  The gun uses standard M4 parts, accessories, etc.  Flip-up sights are also included.  The full metal rail system is M-Lok but includes standard weaver rail adapters that are removable on the bottom and sides (3 total). The pistol grip is contoured for better grip.  Features a quick-change spring system. It’s a solid, hard-hitting, consistent shooting AEG right out of the box.  Tippmann’s performance really shines with their electric gun series.

Tippmann Recon AEG Shorty basically uses a standard 9.6v 1600 battery (or optional 7.4v/11.1v lipo stick or nun-chuck).
Also, the battery not included.
Fits in the crane stock. Midcap M4 magazine is also present.

FPS is around 380 w/.20g BBs