Retro Arms Pre-Built Complete Gearbox – Red Edition

When it comes to upgrading your airsoft rifle, nothing defines performance and reliability more than the heart of your build: the gearbox. The Retro Arms Pre-Built Complete Gearbox (Red Edition) is engineered to deliver unmatched precision, durability, and consistency for serious airsoft players. Designed and manufactured by Retro Arms CZ, this gearbox combines CNC-machined aluminum craftsmanship with premium internals, making it a powerhouse upgrade for your M4 or M16 AEG.

Premium CNC Aluminum Construction

This gearbox shell is precision-machined from a solid block of EN AW 7075 T651 billet aluminum, one of the strongest alloys available in airsoft manufacturing. It’s not just tough—it’s built to withstand the stresses of high-performance parts and demanding field conditions. The durable anodized red finish doesn’t just look aggressive; it also adds an extra layer of protection against wear, ensuring your gearbox keeps its integrity even during extended gameplay.

Reinforced for High Performance

The Red Edition gearbox features reinforcement at all critical stress points, ensuring long-term durability when running powerful springs and high-speed motors. The pre-radiused cylinder windows evenly distribute impact forces across the shell, significantly reducing the chances of stress cracks that often occur with standard gearboxes. This level of engineering is what sets Retro Arms apart as one of the most respected manufacturers in the industry.

Optimized Design for Advanced Builds

The gearbox includes deeper wire channels along the base, giving you a cleaner and more secure wiring setup—essential for high-demand electronic systems. Its quick-change spring guide system allows you to swap springs without completely disassembling your gearbox, saving valuable time during tuning or field adjustments. This makes it a favorite choice among airsoft technicians and competitive players who demand flexibility and reliability.

Fully Loaded with Premium Internals

Unlike most shells that require you to build from scratch, the Retro Arms Pre-Built Gearbox comes ready with high-performance internals, hand-assembled and tested for reliability. The package includes:

• RA CNC gearbox V2 shell

• RA PandoRA gearset 20:1 SS (3mm) for smooth, efficient cycling

• RA 8mm ball bearings for reduced friction and improved gear stability

• RA INOX shims for precision alignment

• RA type C cylinder & standard cylinder head

• RA piston (14.5 teeth) with A1 piston head for consistent compression

• RA tappet plate with delayer chip for perfect feeding

• RA nozzle and ARL components

• RA selector plate and Type J trigger

• Jefftron Leviathan V2 MOSFET for advanced electronic fire control

• M140 spring for high FPS builds

• Dean T connector for efficient electrical conductivity

This setup is purpose-built to deliver around 490 FPS / 1.2 Joules, depending on your configuration. Every gearbox is built and tested in-house by Retro Arms to ensure performance consistency.

Professional Performance, Ready to Drop In

The Retro Arms Pre-Built Gearbox (Red Edition) is designed for compatibility with Tokyo Marui, G&P, Matrix, and other M4/M16 AEG platforms (modification may be required depending on model). With its advanced build and premium parts, this gearbox provides a reliable, high-performance foundation for serious players who want a competitive edge on the field.

Why Choose Retro Arms?

Since its founding, Retro Arms CZ has earned a global reputation for producing some of the most advanced, precision-engineered airsoft components on the market. Known for pushing the limits of performance, Retro Arms products are trusted by competitive players, technicians, and enthusiasts who refuse to compromise on quality.

Final Thoughts

If you’re looking to take your AEG to the next level, the Retro Arms Pre-Built Complete Gearbox (Red Edition) is more than just an upgrade—it’s a complete performance solution. From the CNC-machined aluminum shell to the Jefftron Leviathan V2 MOSFET and carefully selected internal parts, this gearbox is battle-tested and ready to dominate. Whether you’re a competitive player, a tech enthusiast, or simply want the best for your build, the Red Edition gearbox delivers reliability, durability, and precision that will last for years to come.