SA M4 CQB RL M-LOK Gen2 (SA-F04-RL FLEX™ HAL ETU™) – Black / Tan

Why Choose M4 CQB RL M-LOK FLEX™ Gen2 from Specna Arms?

Specna Arms M4 CQB RL M-LOK Gen2 (SA-F04-RL FLEX™ HAL ETU™) is built on a lightweight yet durable FLEX™ RL AR15 nylon body reinforced with glass fiber, offering a realistic matte finish and excellent resistance to wear, outperforming cheaper alloy bodies. This is the RL SAAS model (Specna Arms Accessory System), featuring a more aggressive design compared to standard AR15 receivers. The outer barrel with a 14 mm CCW thread and steel components such as pins, screws, and the ejection port provide strength where it matters. The result is a lightweight yet robust assault rifle platform, ideal for CQB environments and dynamic gameplay. The AR15 (M4) platform ensures intuitive controls. It features an ambidextrous charging handle, clear fire selector, and easy hop-up adjustment through the ejection port. The M-LOK handguard allows mounting accessories such as a foregrip, tactical flashlight, or PEQ box. The Light Ops stock with rubberized cheek rest and QD sling points keeps the setup lightweight. The battery is stored in the buffer tube, requiring a buffer stick battery. Overall, this rifle combines low weight, modern construction, and high-quality Gen2 internals. The FLEX™ Gen2 series stands out with internals such as the Æther™ gearbox, HAL ETU™, metal nozzle, TDC hop-up chamber with Helium™ flat bucking, and a 6.03 mm precision inner barrel.

Key Features of Specna Arms M4 CQB RL M-LOK FLEX™ Gen2

Technical Specifications

• Platform: M4 / AR15
• Series: FLEX™ Gen2
• Length: 670-750 mm
• Weight: 2125 g
• Power Source: AEG
• Unit: HAL ETU™
• Gearbox: Æther™ V2 QSC
• Quick Spring Change: Yes (ESA™)
• Hop-up: TDC
• Inner Barrel: 6.03 mm
• Velocity: 115 m/s
• Bearings: 8 mm
• Connector: T-Dean
• Body Material: Fiber-reinforced nylon
• Handguard: M-LOK
• Thread: 14 mm CCW

Package Contents

• Specna Arms M4 CQB RL M-LOK FLEX™ Gen2
• Hi-cap magazine (300 BBs)
• Flip-up sights
• M90 spring
• Specna Arms stickers
• User manual

Putting the gun into operation

Before you can fire the gun, you must activate the HAL ETU unit and follow this procedure exactly; otherwise, the gun will not respond to the connected battery:

1. Set the fire selector to Safe.
2. Connect the battery and wait 3 seconds until you hear a beep.
3. Pull and hold the trigger for 5 seconds until you hear another beep.
4. The gun is now ready for use.

Warnings

• Springs from some manufacturers are significantly overrated (e.g. an M130 spring may correspond to the power of an M140-150 spring), and their actual rating could exceed the declared durability of the gearbox. We recommend using only the included Specna Arms springs. When using springs from other manufacturers, it is advisable to choose springs rated M120 to prevent possible damage to the gun from a spring that does not correspond to its stated rating.
• When replacing a spring with progressive (irregular) winding, make sure that the end of the spring with the more tightly wound coils is positioned on the spring guide, facing outwards from the gearbox.
• Never store the gun with the battery connected.
• Never store the gun with piston pre-cocking activated. Always release the piston to its forward position before storage to prevent damage to the spring.

Frequently asked questions from our store (FAQ)

How should I charge the battery correctly?

The battery has a main T-Dean connector (red) and a smaller balance connector (white). First plug the charger into the mains, then connect both the balance connector and the T-Dean connector from the battery to the charger, and the charger will charge the battery automatically. Once the battery is fully charged, the charger will safely stop charging and the green indicator light will illuminate. First disconnect the battery from the charger (both connectors) and then unplug the charger from the mains. Handle the balance connector carefully to avoid pulling the wires out of the connector. Pay close attention to polarity when connecting the main T-Dean connector; accidentally connecting (+) and (-) incorrectly may damage the battery or charger.

How durable is the nylon body compared with metal?

The fibreglass-reinforced FLEX™ body is surprisingly strong and more durable than cheap alloys. It is more than sufficient for regular and harder use, although it does not have the same “cold metal feel” as a full-metal body.

Is it worth upgrading the gun straight away?

Usually not. The Gen2 internals (Æther™ gearbox, TDC hop-up, 6.03 mm barrel) are very good for this category. Upgrades make sense later depending on your playing style – typically the hop-up bucking or spring.