Retro Arms is a Czech manufacturer of top-shelf parts and airsoft accessories. Retro Arms products are made only of best-quality materials with the use of, among others, precise CNC machines. Ideal for tuning of all manner of replicas, Retro Arms parts will satisfy even the most demanding Users.

An exceptionally durable reinforced gearbox frame intended for the installation in Umarex HK417 replicas. The gearbox frame was made of an exceptionally strong EN AW 7075 T651 aluminum. The gearbox frame has a QSC system, which allows for a rapid spring change.

The set includes a kit of assembly screws as well as aluminum, ball bearing QSC spring guide.