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JeffTron Leviathan Airsoft Drop-In Programmable MOSFET Module (Type: V3)

ID: 27512 (Mosfet-JT-LEV-V3)
4.5 stars, based on 21 reviews
JeffTron Leviathan Airsoft Drop-In Programmable MOSFET Module (Type: V3)
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  • Easy installation inside the gearbox version V3 by Tokyo Marui standard
  • It uses optical sensor actuated by sector gear cam for perfect semi and full auto fire timing
  • For fire selector position is used optical sensor too - it works with sticker provided with Leviathan
  • Trigger optical sensor with foams can make great hair trigger mod
  • Unique real feel trigger system (RFTS), spring simulates trigger feeling like in the real gun. It adds secondary resistance with release after the fire. Feeling is comparable to shooting with a real AK74
  • Thanks to advanced electronics, Leviathan - V3 can be used with any common gearbox upgrade and gun rate of fire
  • Completely made wiring allows the fastest and the easiest installation into the gun, it is long enough for all kind of weapons with battery placed in front or above the gearbox. No soldering is needed
  • Board covered by conformal coating, it protect Leviathan - V3 against damage from water
The Leviathan - V3 optical is one of the most advanced ETU (electronic trigger unit) on the market.
It has all optical sensors for better handling and durability.
Built-in wireless communication for quick setup using iOS or Android smartphones!
Foam on the trigger makes great hair trigger mode.
Unique Real feel trigger system (RFTS), spring simulates trigger resistance like in the real AK74.
It adds secondary resistance with release after the fire. RFTS was designed by professional gunsmith for more realistic feel from shooting.
External input port and output pads serves for custom accessories.
Real time response for change settings -> immediately test result.
Easy installation into the gearbox instead of the original trigger contacts.
Completely made wiring allows the fastest and the easiest installation into the gun. No soldering is needed.
New functions are for free for every user via online update.

Main Functions:

  • Adds new shooting modes independent for every position on the fire selector (SAFE - SEMI - AUTO)
  • Three adjustable bursts (range 2 - 20 shots)
  • It preserves empty magazine detection like the original gun
  • Rate of fire can be reduce to 40%. It add breaks between shots to reduce RoF. It gives fast trigger response even with very low rate of fire, just like in a real gun
  • Adjustable strength active braking (can be disabled)
  • Pre-cocking function for instant shot on SEMI fire
  • Delay between shots adds time in which isn't possible to shoot, it simulates the delay from gun reload or recoil (range 0,1 - 4,0 seconds)
  • Electronic fuse set sensitivity for high current detection to avoid any damage if something goes wrong
  • Low battery indication for 2S - 4S li-pol and 3S - 4S li-fe
  • Virtual magazine simulates low capacity magazines, it will force the gun to stop shooting when it reach 0. There can be set warning after shot before empty magazine and how it will be reloaded
  • On the board is input port for controlling external devices or Leviathan and output pads for powering the hop-up chamber BBs illumination, powering electric magazine, flashlight, etc.
  • Statistics screen shows shooting output with cycle timing, motor current consumption, rate of fire and temperatures. It allows you to do fine-tune gearbox upgrade
  • Application shows actual battery voltage value. Color lines indicates battery charge status where green is OK, orange will warn after each shot and red will not allow to shoot
  • User can save multiple settings under profiles
  • Update function fixes bugs and adds new features to the device
  • There are three shot counters. Total count every shot during the device lifetime. User counter can be reset by user anytime. Power-up counter is reset by battery connection
  • Error log shows errors made during the device life also can be erased by user
  • For better security wireless connection can be disable by the selector switch (can be deactivated)
  • Leviathan monitors current, voltage and temperature to avoid any damage when something go wrong.
  • Motor vibrates and beeps as a feedback for user
  • Programmed settings are saved in the Leviathan memory immediately after their change, so you can immediately test it and settings aren't lost when is battery disconnected or lost connection with smartphone
  • New functions are for free for every user via online update function


Independent for every position on the fire selector (SAFE - SEMI - AUTO)
  • SAFE: no responding on the trigger pull.
  • Semi: it fires single shot per trigger pull.
  • Semi/BurstX: short trigger pull fires single shot, long trigger pull fires burst.
  • Binary trigger: it fires single shot when trigger is pulled and another single shot when is released.
  • BurstX: gun shoot burst per trigger pull.
  • BurstX/BurstY: short trigger press fires burstX, long trigger press makes burstX+burstY fire.
  • BurstX/Full: short trigger press fires burstX, long trigger press makes auto fire.
  • Full: gun makes auto fire until releasing trigger.
  • Virtual reload: pull trigger to reload virtual magazine

Manufacturer: JeffTron


Mobile Application: You can install it HERE
Device Instructions: You can download installation manual in English HERE [PDF, 4.33 MB]
Compatibility: For Version 3 Airsoft AEG gearboxes
Package Includes: Leviathan drop-in electronic module with complete wiring to front or above the gearbox, 2x Screw with washer for securing device in the gearbox, 2x foams for hair trigger mode (2x 1mm height and 2x 2mm height), Real feel trigger system (RFTS) spring, Sheet with selector plate stickers, Black Leviathan sticker 40 mm, Installation manual in English

Leviathan V3 supports these airsoft guns:

AK47, AK74, Galil, Bizon with V3 gearbox according to TM design
Tokyo Marui AK47 Next Generation
G36, XM8 with V3 gearbox according to TM design
Tokyo Marui G36 Next Generation
AUG, UAR with V3 gearbox according to TM design
Fal/SA58 with V3 gearbox according to TM design
MP5K, UMP with V3 gearbox according to TM design
SIG 55X with V3 gearbox according to TM design

- Installation of this device into the gearbox requires advanced technician skills!
- Please read these informations before installing your device to prevent any damage.
- Short circuit or incorrectly connected battery will cause immediate damage to the device which is not covered by the warranty. It can lead to fire or even battery explosion.
- Disconnect battery, when you aren't using the gun! Otherwise you will fully discharge the battery. Because the device drains small amount of current from the bettery all the time.
- Do not connect battery when gun pointing towards you, another person or an animal.
- Do not modify, repair and put into any kind of liquids or thermal shock the Leviathan - V3.

About JeffTron

Jefftron company was founded in 2011 as a manufacturer of electronic devices for Airsoft electric guns.

21 Customer Reviews

(Write a review)

by Amery M. on 05/23/2022
"Man this thing is great. The app is a little wonky but very solid overall. I haven't tried a Gate Titan to compare but this definitely feels like a top tier mofset with all the possible functionality one could require.
by Zeb N. on 08/16/2021
"This thing is awesome! I love how easy it is to adjust settings with my phone. The trigger response is amazing. The only thing that I wish was different is that you could make it a hair trigger, but the with the way the micro switch is set up is so that it can't have that short of a trigger pull. Nevertheless the trigger pull is still way shorter than your average trigger switch! I would highly recommend this MOSFET to anyone looking to upgrade! I will never go back to a regular trigger switch again!
by Stuart B. on 06/12/2021
"For the price, this is an amazing mosfet. After installing this into my gun the trigger response went from an extremely whiny slow m4, to basically what feels like a dsg. When paired with 13:1 gears and a high torque motor, this thing is a beast. With the small set screw that is included with the trigger it is easy to make the trigger pull next to nothing. And with the precocking turned on the trigger feels amazingly snappy. The bluetooth is also a nice and easy feature.
My only complaint (and it is my fault) is that my semi microswitch broke. I forgot that you have to file down he edges of your selector plate to prevent this. So I only have a full auto. But with the bluetooth I can program it to do semi to comply with field rules.

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