The Sterling submachine gun is a British submachine gun which was in service with the British Army from 1944 until 1994, when it was phased out with the introduction of the L85A1 assault rifle.
ACTION are a new company that have been releasing parts and now have upgraded to Snipers and AEGs. The latest in the line up is the SL MK4 AEG. The Sterling. It's made out steel, it's small and compact, it's beautiful!
You're probably wondering why this isn't a GBBR. It's because the way the magazine feeds. The magazine is made out of metal and holds 40 BBs and feeds like a systema. Remember, gas rises and since the magazine goes in through the side, having the gas feed the BBs through properly would be impossible unless you turn the Sterling 90 degrees to the left, but then the hop up would make the BBs fly to the left.
There isn't much space for a battery to be stored so ACTION have made their own 7.4v battery that fits in the handguard. It doesn't have the highest rate of fire at the moment but ACTION MAY release a 11.1v battery some time in the future. The hop is very strong so you may want to use heavier BBs if you want it to be accurate.