Description
The Jefftron Leviathan optical unit for version 3 gearboxes is one of the most advanced microprocessor-controlled ETU (electronic trigger unit) systems on the airsoft market! The Jefftron Leviathan V3 Optical monitors the gear position in real time using two optical sensors. The Leviathan unit can be easily programmed via Bluetooth using a smartphone (iOS or Android).
With the included foam pad that can be attached to the AK trigger mechanism, the trigger travel can be adjusted to be extremely short, achieving a so-called "hair trigger".
The Leviathan V3 Optical unit supports RFTS technology (Unique Real Feel Trigger System), where a separate spring mechanism simulates the trigger response of a real AK74. Jefftron worked with a gunsmith specializing in firearms to design the RFTS for a realistic trigger feel.
Two-stage trigger
In addition to the RFTS solution, this product includes a new "two-stage trigger" with a realistic pre-travel and a distinct break point.
The two-stage trigger is an adapter made from 3D-printed plastic and spring steel that replicates the behavior of a two-stage trigger found in real firearms, allowing the user to know exactly when the shot will fire. This improves accuracy and creates a realistic shooting feel.
The two-stage trigger operates in two clearly defined stages:
- In the first stage, the trigger is pulled smoothly until it hits the wall.
- In the second stage, the trigger weight increases until the wall breaks.
- The "click" of the second stage fires the shot.
This solution was designed by gunsmith Tomas Linhart, like other Jefftron RFTS-family solutions. The two-stage trigger differs from the RFTS-V3 spring system included with the Leviathan V3 and offers an improved trigger response. It is also more compatible with different gearbox models than the traditional RFTS spring system. For example, it fits Retro Arms gearboxes directly without modifications.
The Leviathan series offers various expansion options through an output port on the board. (Installing additional accessories requires soldering on the PCB. Leave modifications to a professional.)
The Leviathan brings a wide range of new features to your AEG and improves existing ones. With this unit, you can control your gun’s fire modes, rate of fire (ROF), pre-cocking, active braking, protect LiPo/LiFe batteries from over-discharge, and much more.
The Leviathan unit is installed entirely inside the version 3 gearbox, replacing the traditional trigger switch assembly. The unit comes with pre-installed wiring, including a 40A mini fuse and Deans/T-connectors. No soldering is required for the basic installation!
What features does the Leviathan unit provide?
- Adjust and add all fire modes in any selector position (SAFE - SEMI - AUTO).
- Three different burst fire modes. Each mode’s burst length can be set between 2 - 20 rounds.
- Option to stop firing when the magazine is empty. Magazine change can be signaled to the gun via an additional switch (sold separately).
- Limit the gun’s rate of fire by adding pauses between shots while maintaining an extremely fast trigger response.
- Adjustable active brake strength, which can also be disabled.
- "Pre-cocking" function for instant semi-auto response.
- Option to add a delay between shots to simulate the effect of recoil on shooting speed. Delay can be set between 0.1 - 4 seconds.
- Low voltage warning when using LiPo or LiFe batteries. Works with 2S - 4S LiPo and 3S - 4S LiFe batteries.
- Store multiple configuration profiles.
- Software displays actual battery voltage with a color-coded indicator for charge level.
- Three separate shot counters: total lifetime shots, user-resettable counter, and a counter that resets when the battery is disconnected.
- Error log records all errors during the unit’s lifetime.
- Leviathan V3 monitors current, voltage, and temperature, protecting components from damage in case of failure.
- Motor vibrates and beeps to provide feedback to the user.
- Settings are saved in real time to the Leviathan V3 memory, so you won’t lose them if Bluetooth disconnects or the battery is removed during adjustment.
Programmable fire modes:
Each mode below can be assigned to any selector position (SAFE - SEMI - AUTO).
- SAFE: Trigger pull does nothing, gun is on safe.
- SEMI: Fires one shot per trigger pull.
- SEMI/BurstX: Short pull fires one shot, long pull fires a preset burst.
- "Double trigger": Fires once on pull and once on release (two shots per pull).
- BurstX: Fires a burst with one pull.
- BurstX/BurstY: Short pull fires burstX, long pull fires burstX followed by burstY.
- BurstX/Full: Short pull fires burstX, long pull fires full auto.
- Full: Fires full auto as long as the trigger is held.
- Virtual reload: Pull the trigger to virtually reload the magazine.
SPECIFICATIONS:
- The Leviathan circuit is coated with lacquer for water protection.
- Pre-cocking requires an anti-reversal latch in the gearbox.
- Designed to operate with batteries up to 17V. Compatible with 8.4 - 12V NiMH and 7.4 - 14.8V lithium-based batteries.
- Parts removed during installation: cut-off lever, original trigger, switch contacts, and safety parts. The original trigger can still be used with the Leviathan board.
Leviathan manual: Download the installation and user manual HERE
Download the Leviathan app: https://www.jefftron.net/application
Package Includes:
- Leviathan - V3 Optical with Deans/T connector and 40A fuse slot. Motor wires with standard motor connectors.
- Screw set for securing Leviathan inside the gearbox.
- Foam pad for trigger sensitivity adjustment.
- RFTS mechanism for realistic trigger feel.
- English installation manual.

https://youtu.be/fIbqSugvzbU
SAFETY INSTRUCTIONS:
- Installing the unit inside the gearbox requires knowledge of airsoft gun mechanics.
- Read the manual before installation to avoid damage!
- A short circuit or incorrect battery connection will immediately damage the unit! Incorrect wiring voids the warranty and may cause the battery to explode!
- Always disconnect the battery when the gun is not in use! Otherwise, the unit may slowly drain the battery, rendering it unusable. When connected, Leviathan draws a small standby current.
- Always ensure the barrel is pointed in a safe direction before connecting the battery!
- Do not modify, repair, or expose the Leviathan V3 board to liquids or heat.





























