Contact Us Tel:(626) 286-0360 Store Locations
Phone Support M-F 7am-5pm PST
Browse by Type or Category
AIRSOFTCON 2026 - October 17, 2026

JeffTron Leviathan Airsoft Drop-In Programmable ETU Module (Type: V2 Optical - Black Speed Trigger / Wired to Stock)

25 Customer Reviews

by Robert C. on 11/19/2019
"One of the best on the market. I would highly recommend either taking your time to install if you are a techy sort of person, or having a professional do it.

If installed correctly the Jefftron Leviathan V2 is an incredible piece of technology. I have installed 3 of them, and 2 out of the 3 went absolutely perfect. The one that didn’t go as well was partly do to user error and gearbox fitment. After heavy use, though, the motor connects fell off, and had to be re-soldered, which is why I recommend for more advanced users.

I love the Bluetooth controls, and the error log is invaluable. Everything is very seamless to adjust; any where from active motor braking, to rate of fire, to fire modes, etc. You can see your mosfet temp, your motor amperage, the works! It’s incredible.

Overall, best investment for the more avid airsofter.
by Zachariah D. on 11/16/2019
"Absolutely love it! Just installed into my echo 1 SCAR and fit perfectly. Had to trim selector plate since it’s a different design than m4 but it was really easy to do. Bluetooth makes it so much easier to program than other mosfets I’ve had and it has some really cool settings. I particularly like the binary trigger mode.
by CALEB K. on 04/02/2019
"So far I’m loving this thing! The install was quite easy as I didn’t have to do any filing or grinding. I spent a bit of time making sure the sector gear and fitment was good.
I love being able to easily choose what fire modes are assigned to each fire selector position. I also enjoy the adjustable trigger. Currently, I have an amazing trigger response and I can enjoy double trigger (which is something I haven’t seen yet).

My only gripe is that the switches under the selector plate are a pain. The switches themselves seem a tad bit short and don’t always register with my plate. I will try to adjust my selector plate or get a new one that fits better as it mostly stays in SEMI, and sometimes will actually register if I’m in SAFE air AUTO.

Also, my V2 gearbox is by VFC. Judging by the notes (and the install video), some are slightly different, hence the “no need for filing/grinding.” Others may differ.
by two c. on 01/28/2026
"OK, this is my second review because I have dealt exclusively with the V2 Leviathan, this is my experience with the V3 Leviathan

It operates as it should, my biggest fault would be not being able to shorten the trigger throw, but the optical sensor can pick it up very early in the arc when tuned correctly

Everything else is exactly what I would come to expect that I've dealt with in the V2 version

With the exception of the wiring. The wiring is an absolute joke. I fried my first one as it's literally barely barely long enough to loop around from the exit at the front of the gearbox to the back of the gearbox where the motor wires drop through

Because it's such a tight fit and I had to disassemble my LCT a few times troubleshooting a different problem the wires got snagged on reassembly pretty much every single time. That should've been my cue to do what I did with the replacement that I bought and lengthen the wires

Because one of the wires got nicked, as soon as I plugged in the battery I got a spark and the foul smell of electrical components being fried. Fortunately I was quick enough to unplug it before there was an absolute catastrophe. But it was enough to fry one of the chips and render the Leviathan useless

As a stock product this is a huge fault and I would never ever attempt to install another one without adding about an inch to each of the leads which connect the motor which is what I did to make it work.

Should not need to be done in the first place, but it's not hard to do I will admit

Other than that expect only good things
by Catherine E. on 12/24/2022
"Overall almost 100% perfect, with that being said the fire select can sometimes be finicky and I’ve had to re configure it even time I use my gun, not that bad however it’s performance in cold weather is problematic, the fire selector becomes extremely finicky however this can be fixed by messing with the app, in edition I had problems with the mosfet acting how it does when the battery is nearly dead even with a full battery, these issues only apply extremely cold weather (I had these issues at around 18 degrees F) as I said before this is an extremely solid option However you should be aware of these issues
by Gabe D. on 09/03/2020
"I give this a 4 out of 5 because the motor connecters from the wires broke too easily, its a lot of work to get it installed. I highly suggest you get it installed ny a professional.

Pros:
The app really works, the system tells you what is wrong and how to fix it
Everything works out

Cons:
Have to mod gearbox
Motor connecters broke too easily

Again highly suggest you get it installed by professional
by Chase Z. on 05/24/2020
"Installation can be very finicky and the active break is not adaptive like the Gate though if you just go for lower speeds it will be fine im currently at 53 RPS and no problems I wouldn't recommend for a DSG but besides that its break
by Sam B. on 07/10/2019
"I installed it in my friends Krytac LVOA-C. Required a little modification to the gearbox shell (as I expected). The problem I had, and maybe I just got a lemon or Evike or Jefftron screwed up, but you are supposed to get a Retro Arms "J" style trigger with the unit. Mine included a Type "A" trigger, which didn't fit. I made it fit by cutting a part off but I found that odd. Also, when I opened the packaging, the negative motor connector had broken off. This was not a huge deal to me as I am a tech and have spares. But later doing more work on the gun, the positive motor connector broke off. I replaced that as well. I contacted Jefftron about this and they were very helpful and offered to send me the correct trigger free of charge and to fix the motor connectors if I sent it into them.

Overall, 4/5 stars. I know it's a great product. My friend has two of them. I just had a hiccup when I got mine but it wasn't a big deal for me.

I would still highly recommend this MOSFET if you're looking for great performance.
by Jeffrey M. on 06/15/2019
"Overall I love this mosfet but as said by another review the wires leave something to be desired I’ve been chasing intermittent shorts and the motor connector snapped on me I’ll fix It but as I said solid mosfet I plan on getting another
by Brendan P. on 04/23/2019
"This mosfet is amazing for the price. You get a lot of cool features such as the double trigger. I really like the fact that it comes with an adjustable trigger , but the screw that it comes with is very small and has a tendency to fall out if rattled too much. But that can easily be fixed with Teflon tape. The app is easy to use and has lots of cool Features that are easy to adjust. The only problem I have with this mosfet is the fact that the signal wire (the small light blue wire) is very thin and easy to break which is what happened to mine , but other than that this mosfet is great and provides amazing trigger response.