Outside of the USA, new HPA airsoft technologies are also being developed, and you can find one of these in Poland where it is the HPA centre in Europe. Here HPA Airsoft EU goes over the Kuba_T1000 Nemesis HPA Engine which is now released though this was in development since 2011.

More choices for HPA engines to be used for airsoft with Kuba_T1000 releasing his own Nemesis Engine as shown by DIYminigun in this video... "CNC machined body, with One Moving Piston technology designed by me in 2001year guarantees long reliability time, and provides great performance for good price compared to other solutions."