M4 FLEX Gen.2 Light Ops HAL ETU Half-Tan SA-F04-RL

Specna Arms SA-F04-RL airsoft replica from the FLEX Gen.2 series in Half-Tan: a light, compact M4 carbine in reinforced polymer that brings advanced-replica components such as HAL ETU electronics, the Magnus rotary hop-up and the reinforced Æther gearbox to an agile platform.

Features and technical specifications

• Manufacturer: Specna Arms
• Model: SA-F04-RL FLEX Gen.2 Light Ops Stock
• Manufacturer code: SPE-01-047444
• EAN: 5902543207272
• Replica of: M4 / AR15 / M16
• System: electric AEG
• HAL ETU electronics – already initialized as part of our READY TO PLAY package.
• HAL ETU functions: Hall-effect magnetic trigger sensing, active brake, binary trigger, 5-level trigger sensitivity (20 to 100%), 6-level pre-cocking, programmable automatic modes (full auto, semi, 3-round or 5-round burst), programmable semi modes (semi, binary, AUG, sniper), trigger-based programming, low battery alarm, brushless motor compatibility
• Gearbox: Æther V2 with reinforced shell and front end, spring release function, trigger adjustment and inspection windows
• Hop-up: TDC Magnus rotary chamber with Helium Flat Hop bucking
• Inner barrel: 6.03 mm precision barrel, 235 mm long
• Internal components: sealed aluminium nozzle, steel gears, 8 mm bushings, polycarbonate piston with steel teeth
• Spring: ESA quick-change system
• Power output: below 1 J
• Materials: nylon fibre reinforced polymer with a matte finish, aluminium and steel; flash hider, outer barrel, dummy bolt, ejection port cover, fire selector, bolt release button, magazine catch, stock QD mounts, pins and charging handle in metal
• Handguard: polymer M-LOK with 20 mm side rails
• Top rail: full-length 20 mm
• Stock: Light Ops retractable stock, 6-position adjustable, with rubber anti-slip inserts on both sides of the cheek rest, curved rubber butt pad and QD mounts
• Battery compartment: in the stock tube
• Grip: ergonomic pistol grip
• Controls: enlarged ambidextrous fire selector and magazine release, functional bolt catch
• Sights: folding iron sights
• Connector: Deans (T-connect)
• Length: 670–750 mm
• Weight: 2125 g
• Colour: Half-Tan
• Package contents: 300-round S-Mag Hi-Cap magazine, cleaning rod, Allen key, Deans to mini Tamiya adapter
• Battery and charger: not included

Shape and style

The Half-Tan colour scheme pairs tan parts with black, giving the carbine a modern, operational look that matches coyote and multicam kit. The pared-down, lightweight Light Ops stock provides a stable cheek weld and a curved butt pad that sits naturally in the shoulder. Enlarged controls on both sides make the replica comfortable for left-handed shooters too, while the M-LOK handguard and 20 mm rails leave room for optics, lights, grips and accessories.

Performance

The Magnus chamber allows fine, stable hop-up adjustment, and the Helium Flat Hop bucking helps keep the BB trajectory consistent. The ESA system lets you change the spring quickly, without opening the gearbox. With Hall-effect trigger sensing and an active brake, the HAL ETU delivers a crisp, precise trigger response, and the programmable modes adapt the trigger behaviour to your playing style.

In the field

At 670 mm with the stock collapsed and around 2.1 kg, the SA-F04-RL moves nimbly in CQB and between buildings, while the precision barrel and Magnus hop-up make it effective in woodland games too. Housing the battery in the stock keeps the handguard free for accessories, and the low overall weight is appreciated during longer game days and MilSim events.

Specna Arms recommends a 7.4 V battery with an M90 spring. In configurations for the Italian market, higher voltages may increase the risk of premature piston engagement.

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READY TO PLAY package included in the price: each replica is individually tested, inspected and checked before sale.