Get your airsoft rifle back into the fight with the CYMA Standard Complete 8mm Version 2 Gearbox for M4 Series AEGs (Rear Wired / With Motor) — a pre-assembled, field-ready power unit built for performance, reliability, and easy installation. CYMA’s decades of expertise in precision engineering make this gearbox the perfect solution for players who want to restore or upgrade their AEG with a dependable core component.

Whether you’re building a custom rifle or replacing a worn-out gearbox, this Version 2 complete gearbox provides the perfect balance of durability, compatibility, and power efficiency — all with an included long-type motor for plug-and-play convenience.

Built for Durability and Longevity

CYMA designed this gearbox with a reinforced metal alloy shell, capable of withstanding the stress of high-torque springs and demanding full-auto fire. The upgraded structure helps reduce flexing and misalignment, ensuring smooth gear engagement and consistent power delivery.

Inside, the gearbox features precision-machined internals that maintain tight tolerances, reducing friction and wear over time. Combined with the ball bearing spring guide, this setup ensures a more efficient energy transfer with less resistance, extending the lifespan of your components while improving overall performance.

Smooth and Efficient Operation with 8mm Metal Bushings

The 8mm metal bushings are one of the highlights of this CYMA gearbox. Designed to handle both high-torque and high-speed setups, these bushings minimize friction between the gears and shell, providing smoother rotation and better mechanical stability.

When compared to smaller or plastic bushings, the 8mm metal versions deliver enhanced heat dissipation and mechanical strength — allowing for longer play sessions and fewer maintenance issues. The result is a gearbox that cycles smoothly, efficiently, and reliably, game after game.

Pre-Wired for Rear Battery Configuration

This gearbox is wired to the rear, making it ideal for AEGs with full stocks or buffer tubes designed to house rear-wired batteries. It uses low-resistance wiring and a small Tamiya connector to ensure consistent electrical flow, reducing voltage drop and improving trigger response.

Whether you’re using a standard NiMH or LiPo setup, the low-resistance wiring maximizes electrical efficiency — giving you crisp, responsive trigger pulls and consistent rate of fire.

Includes OEM Spec Long-Type Motor

Unlike many bare gearbox shells, this CYMA version includes an OEM specification long-type motor — perfectly matched for M4 and M16 AEG platforms. The motor provides smooth, consistent torque for both semi and full-auto fire, making it an excellent choice for standard and upgraded spring configurations.

The inclusion of a motor makes this gearbox a true drop-in unit, ready to install with minimal modification. It’s a complete, all-in-one solution for players who want to spend less time tuning and more time playing.

Perfect for M4 / M16 Builds and Upgrades

The CYMA Standard 8mm Version 2 Gearbox is compatible with most M4 and M16-style airsoft AEGs. Its Version 2 trigger assembly ensures broad compatibility with common receiver designs, making it a great option for replacements, custom builds, or upgrade projects.

Pair it with your preferred hop-up unit, inner barrel, and external components to create the ultimate battle-ready rifle. CYMA’s plug-and-play design simplifies installation and provides reliable performance right out of the box.

Specifications:

• Manufacturer: CYMA

• Gearbox Type: Version 2 (Complete Assembly)

• Wiring: Rear Wired (Low Resistance)

• Bushing Size: 8mm Metal Bushings

• Spring Guide: Ball Bearing Metal Guide

• Connector Type: Small Tamiya

• Motor: OEM Spec Long Type Motor Included

• Material: Reinforced Metal Alloy

• Compatibility: Most M4 / M16 AEG Platforms

Why Choose the CYMA Standard 8mm Gearbox?

✅ Reinforced shell for maximum durability
✅ 8mm metal bushings for smooth gear performance
✅ Ball bearing spring guide for better efficiency
✅ Rear wired with low-resistance connectors
✅ Includes long-type motor for easy installation

About CYMA

Founded in 2000, CYMA Airsoft has become one of the most trusted names in the airsoft industry. Renowned for their rugged and reliable AEGs, gearboxes, and accessories, CYMA combines innovative engineering with long-standing craftsmanship to deliver products that perform under pressure.

With extensive experience producing training weapons for law enforcement and military clients, CYMA has applied real-world expertise to their airsoft designs. From casual players to competitive professionals, CYMA ensures every user can rely on their equipment to deliver power, precision, and reliability in the field.

When you choose CYMA, you’re investing in battle-tested engineering built for victory.