- Steel gray receiver finishing - Free lipo battery included - Geissele style Super Modular Rail MK15 M-LOK 10.5'' rail system for HK416 - Matte finish full metal receiver - Rotary hop up system - Deep-engraved realistic full trades - Enhanced metal gearbox with 8mm bearing bushing - Standard Ver. 2 gearbox with quick spring change design. Spring can be changed within 10 mins without dissemble - 300 rds Hi-cap magazine included - Marking version