An interesting comparison of Version 3 gearboxes from Retro Arms and X High Tech/Combat Gear is made by Hokum of Airsoft Ukraine... "From the technical point of view the ultimate difference between these two is in the process how they were made. The X High-tech gearbox is casted first and then milled (or if you prefer - polished with CNC). The one from Retro Arms is completely CNC machined out of the solid block of aluminium AW EN7075 T651. This difference can be easily noticed on parts like spring retaining pins, parts which hold the cylinder or selector plate spring guide."

Read the full review here.