SA-F04 FLEX Gen.2 HAL ETU Airsoft rifle Olive

Introducing the SA-F04 FLEX Gen.2 HAL ETU airsoft carbine in Olive — a meticulously engineered Specna Arms platform designed to elevate performance, reliability, and field versatility. Grounded in Specna Arms’ reputation for precision, every component on this Gen.2 FLEX model has been redesigned to outpace the demands of intense skirmishes while remaining accessible to players who want out-of-the-box readiness and long-term upgrade potential.

Why this Flex Gen.2 stands out

The Flex Gen.2 platform is built around a modular, high-strength chassis that combines nylon-fibre reinforced polymer with critical metal components. This pairing delivers a light, balanced feel without sacrificing durability, making it ideal for rapid transitions between CQB and longer-range engagements. The olive finish provides a tactical, non-reflective profile that blends into woodland and urban environments alike.

Advanced internals for precision and consistency

• Top Down Center Hop-Up (TDC Magnus) chamber with a European Patent (015052069-0001) for ultra-stable, repeatable BB release and fine-tuning of backspin for accuracy at varied ranges.
• Helium Flat Hop Eraser to improve the stability of the BB’s undercurve, reducing hop variance across shots.
• Aluminium sealed nozzle for consistent air seal and reduced shot-to-shot inconsistencies.
• Æther™ Gearbox with a reinforced frame and pre-cocking AoE inspection windows — designed for long-life operation and easier maintenance checks.
• 8mm plain bearings and steel gears paired with a polycarbonate piston with full steel slats and a high-precision 6.03mm barrel for reliable, accurate shoots.
• ESA™ quick spring change system enabling rapid power changes on the field to adapt to different play areas without tools.

HAL ETU — intelligent fire control and programmability

The HAL™ (Hardware Aware Logic) ETU system brings smart control to your rifle with magnetic sensor-based trigger detection and Hall effect actuation. It delivers an active brake, a binary trigger option, and highly adjustable trigger sensitivity (5 levels from 20% to 100%), giving you tactile, predictable trigger feel. The HAL ETU also includes:

• Adjustable pre-cocking across 6 levels for improved shot consistency, especially in semi- or burst-fire modes.
• Auto programmable fire modes (full auto, semi, 3-round burst, 5-round burst) and semi-programmable modes (semi, binary, AUG, sniper) for adaptable engagements.
• Easy programming via trigger interface and a built-in low battery alarm to prevent mid-game drop-offs.
• Compatibility with brushless motors for cleaner power delivery and extended motor life.

Ergonomics, handling, and field-ready features

The HAL ETU-equipped rifle uses a durable, lightweight chassis that minimizes fatigue during extended games. The Light Ops Stock provides a sleek, low-weight silhouette with a modern design and non-slip rubber cheek stickers for secure aiming. The distinctive curved rubber stock foot sits comfortably against the shoulder, helping maintain a stable sight picture during rapid follow-up shots. Other noteworthy design elements include enlarged manipulators on both sides (selector and magazine release) and a functional bolt-catch for intuitive operation under pressure.

Performance-oriented build details

• Specna Arms proprietary 6.03mm precision barrel for consistent accuracy and tight groupings at typical skirmish ranges.
• Metal externals and reinforced frame coupled with a nylon reinforced body result in a robust platform capable of withstanding frequent field use.
• Ready for M140 springs to meet higher-power field regulations while maintaining reliability under load.
• Internal design highlights include 8mm bearings, a press-fit nozzle, and carefully chosen materials that balance weight with durability for real-world play.
• Quick-swap compatibility with common upgrade paths and accessories, ensuring your rifle remains competitive as you refine your loadout.

Who this rifle is ideal for

Ambitious players who want a high-performance platform out of the box, with room to tune and customize as they gain experience. It’s perfect for players who value field adaptability, long-term reliability, and a system that supports advanced fire modes and battery options. Whether you’re building a precision setup for mid-range engagements or a fast-response CQB carbine, the SA-F03 FLEX Gen.2 HAL ETU Olive is designed to scale with your skills.

Maintenance and best-practice tips

Regular lubrication of moving parts, periodic inspection of the reinforced frame, and checks of the hop-up and nozzle seal will keep this platform performing at peak levels. Take advantage of the ESA™ quick spring change system to experiment with different spring configurations in different field scenarios. Always verify battery compatibility with the HAL ETU and ensure a brushless motor setup is properly configured to avoid overheating during extended games.

For more about related gear, explore the Specna Arms collection (collections/specna-arms) and related fields such as high-performance carbines (collections/airsoft-carbines). You can also find HAL ETU upgrade paths and compatible options in the HAL ETU family (collections/hal-etu).

Battery included	No
Bearings diameter [mm]	8
Blow Back	No
Colour	Olive
Product length [cm]	75.50
Product weight [g]	2145
Power supply	Electric
Material	Aluminum Plastic
Muzzle velocity [FPS]	410
Fire mode	Full-auto Adjusted burst Semi-auto
Gearbox version	Gearbox v2
Hop-Up	Yes
Inner barrel length [mm].	230
Length minimal [mm]	670
Magazine capacity [pcs.]	125
MOSFET/ETU	Yes
Quick Spring Change system	Yes
Type of plug	DEANS / T-connect
Type of thread on the barrel	14mm CCW