The Jing Gong SIG 550 at RSOV.com, at around £46.99, but don't expect the Swiss Arms markings included. We wonder if this time the MOSFET that they installed in their full-metal M4A1 is also included here, though the price makes us doubt it... "Jing Gong Sig 550 AEG with metal barrel, bipod, front and rear sight sets comes with scope mount rail, battery and battery charger."