NBU cylinder set for G3-A3/A4/SG-1/MC51/SAS

Full NBU air system for power increase. Include chromium-plated cylinder, polycarbonate back pressure piston head with the bearing, stainless cylinder head with double O-rings and acetal nozzle with O-ring.

What is NBU? : NBU parts have increased inner diameter to hold more air capacity. It is ussually cylinder, piston head, cylinder head and nozzle. Typically sold as a complete set.  It is recommended use M120 springs or higher to reach proper effect.